All Wiring Diagrams for GMC Cab & Chassis C1998 2500

AIR CONDITIONING

5.0L

5.0L (VIN M), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• (engine harness, 22 cm from ebcm breakout)
• (engine harness, near ebcm breakout)
• (engine harness, near egr valve breakout)
• (exc 4.3 l)
• (fwd lamps harn, 5 cm from right headlamp breakout)
• (hvac harness, 4 cm from recirc door breakout)
• (hvac harness, 8 cm from recirc door breakout)
• (i/p harn, 28 cm from cluster breakout)
• (i/p harness, behind center of dash)
• (right side of dash)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse/relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c ctrl
• A/c disable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c req
• A/c switch
• Air temp dr sensor
• Aux fan ctrl
• Aux fan fuse 30a
• Auxiliary cooling fan motor
• Auxiliary cooling fan relay (exc 4.3l) (in underhood fuse/relay center)
• Battery
• Blower fuse 3 50a
• Blower motor (under right side of dash)
• Blower resistor (on blower motor housing)
• Blower switch
• Center
• Defogger element
• Diode
• Front mode door motor (on front a/c-heater housing)
• Front temperature door motor (on front a/c-heater housing)
• Fuse block
• G101 (right front of engine compartment)
• G119 (top right side of cylinder head)
• G120 (right side of engine)
• G201
• G202 (behind left side of dash)
• Ground
• High blower relay (on top of front a/c-heater housing)
• Hot at all times
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign e fuse 10a
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Pnk
• Rear defogger system
• Recirculation door motor (on front a/c-heater housing)
• Red
• Relay ctrl
• S103
• S110
• S128
• S146
• S147 (engine harn, near egr breakout)
• S185
• S186
• S212 (i/p harn, behind center of dash)
• S243
• S244
• S268
• S298
• Sw sig
• Tan
• Underhood fuse-relay
• Underhood fuse-relay center
• Valve ctrl
• Vehicle control module (left side of engine compt)
• Water valve (suburban, utility, crew cab only) (right center of intake area)

5.0L (VIN M), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• 22 cm from ebcm breakout)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse-relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c control
• A/c disable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c req
• A/c switch
• Blower switch
• Diode
• Fuse block
• G119 (top right side of cylinder head)
• G120 (right side of engine)
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign e fuse 10a
• Ignition
• Near egr valve breakout)
• Off
• Pnk
• S146 (eng harn, pnk
• S185
• S186
• S268 (i/p harn, behind center of dash)
• Sw sig
• Underhood fuse-relay center
• Vehicle control module (left side of engine compt)

Heater Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Heater Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (hvac harn, 8 cm from recirc door breakout) s244
• (i/p harn, 24 cm from i/p cluster breakout)
• (right side of dash) g201
• Air temp dr sensor
• Battery
• Blower fuse 3 50a
• Blower motor (under right side of dash)
• Blower resistor (on blower motor housing)
• Blower switch
• Defogger element
• Front mode door motor (on front a/c-heater housing)
• Front temperature door motor (on front a/c-heater housing)
• Fuse block
• G202 (behind left side of dash)
• Ground
• High blower relay (on top of front a/c- heater blower housing)
• Hot at all times
• Hot in run
• Htr-a/c fuse 12 25a
• Hvac control module
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Rear defogger system
• Recirc ctrl
• Recirculation door motor (on front a/c-heater housing)
• Red
• S110 (engine harness, near ebcm breakout)
• S243 (hvac harn, 4 cm from recirc door breakout)
• S268 (i/p harness, behind center of dash)
• S298
• Tan
• Underhood fuse-relay center

5.7L

5.7L (VIN R), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• (engine harness, 22 cm from ebcm breakout)
• (engine harness, near ebcm breakout)
• (engine harness, near egr valve breakout)
• (exc 4.3 l)
• (fwd lamps harn, 5 cm from right headlamp breakout)
• (hvac harness, 4 cm from recirc door breakout)
• (hvac harness, 8 cm from recirc door breakout)
• (i/p harn, 28 cm from cluster breakout)
• (i/p harness, behind center of dash)
• (right side of dash)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse/relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c ctrl
• A/c disable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c req
• A/c switch
• Air temp dr sensor
• Aux fan ctrl
• Aux fan fuse 30a
• Auxiliary cooling fan motor
• Auxiliary cooling fan relay (exc 4.3l) (in underhood fuse/relay center)
• Battery
• Blower fuse 3 50a
• Blower motor (under right side of dash)
• Blower resistor (on blower motor housing)
• Blower switch
• Center
• Defogger element
• Diode
• Front mode door motor (on front a/c-heater housing)
• Front temperature door motor (on front a/c-heater housing)
• Fuse block
• G101 (right front of engine compartment)
• G119 (top right side of cylinder head)
• G120 (right side of engine)
• G201
• G202 (behind left side of dash)
• Ground
• High blower relay (on top of front a/c-heater housing)
• Hot at all times
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign e fuse 10a
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Pnk
• Rear defogger system
• Recirculation door motor (on front a/c-heater housing)
• Red
• Relay ctrl
• S103
• S110
• S128
• S146
• S147 (engine harn, near egr breakout)
• S185
• S186
• S212 (i/p harn, behind center of dash)
• S243
• S244
• S268
• S298
• Sw sig
• Tan
• Underhood fuse-relay
• Underhood fuse-relay center
• Valve ctrl
• Vehicle control module (left side of engine compt)
• Water valve (suburban, utility, crew cab only) (right center of intake area)

5.7L (VIN R), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• 22 cm from ebcm breakout)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse-relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c control
• A/c disable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c req
• A/c switch
• Blower switch
• Diode
• Fuse block
• G119 (top right side of cylinder head)
• G120 (right side of engine)
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign e fuse 10a
• Ignition
• Near egr valve breakout)
• Off
• Pnk
• S146 (eng harn, pnk
• S185
• S186
• S268 (i/p harn, behind center of dash)
• Sw sig
• Underhood fuse-relay center
• Vehicle control module (left side of engine compt)

Heater Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Heater Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (hvac harn, 8 cm from recirc door breakout) s244
• (i/p harn, 24 cm from i/p cluster breakout)
• (right side of dash) g201
• Air temp dr sensor
• Battery
• Blower fuse 3 50a
• Blower motor (under right side of dash)
• Blower resistor (on blower motor housing)
• Blower switch
• Defogger element
• Front mode door motor (on front a/c-heater housing)
• Front temperature door motor (on front a/c-heater housing)
• Fuse block
• G202 (behind left side of dash)
• Ground
• High blower relay (on top of front a/c- heater blower housing)
• Hot at all times
• Hot in run
• Htr-a/c fuse 12 25a
• Hvac control module
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Rear defogger system
• Recirc ctrl
• Recirculation door motor (on front a/c-heater housing)
• Red
• S110 (engine harness, near ebcm breakout)
• S243 (hvac harn, 4 cm from recirc door breakout)
• S268 (i/p harness, behind center of dash)
• S298
• Tan
• Underhood fuse-relay center

6.5L

6.5L (VIN F), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, 30 cm from breakout to ebcm)
• (engine harn, near diode)
• (engine harness, near ebcm breakout)
• (hvac harness, 4 cm from recirc door breakout)
• (hvac harness, 8 cm from recirc door breakout)
• (i/p harn, 24 cm from cluster breakout)
• (i/p harness, behind center of dash)
• (right side of dash) g201
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse/relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c ctrl
• A/c disable
• A/c enable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c switch
• Air temp dr sensor
• Aux fan ctrl
• Battery
• Blower fuse 3 50a
• Blower motor
• Blower resistor (under right side of dash, on heater housing)
• Blower switch
• Center
• Defogger element
• Diode
• Front mode door motor (under dash on heater- a/c case)
• Front temperature door motor (under dash on heater- a/c case)
• Fuse block
• G120 (right side of engine)
• G202 (behind left side of dash)
• Ground
• Heater and a/c control module
• High blower relay (under dash on top of heater-a/c case)
• Hot at all times
• Hot in run
• Hot in run or start
• Htr-a/c fuse 12 25a
• Ign 1 fuse 10a
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Pnk
• Powertrain control module (left rear of engine compt)
• Rear defogger system
• Recirculation door motor (under dash on heater- a/c case)
• Red
• S107
• S110
• S147 (engine harn, 4 cm from starter motor breakout)
• S185
• S186
• S212 (i/p harn, behind center of dash)
• S243
• S244
• S268
• S298
• Tan
• Underhood fuse-relay

6.5L (VIN F), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• 30 cm from ebcm breakout)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse-relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c control
• A/c disable
• A/c enable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c switch
• Aux fan ctrl
• Blower switch
• Diode
• Fuse block
• G120 (right side of engine)
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign 1 fuse 10a
• Ignition
• Off
• Pnk
• Powertrain control module (left rear of engine compt)
• Recirculation door motor (under dash, on heater- a/c case)
• S185
• S186
• S268 (i/p harn, behind center of dash)
• Underhood fuse-relay center

6.5L (VIN S), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), A/C Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, 30 cm from breakout to ebcm)
• (engine harn, near diode)
• (engine harness, near ebcm breakout)
• (hvac harness, 4 cm from recirc door breakout)
• (hvac harness, 8 cm from recirc door breakout)
• (i/p harn, 24 cm from cluster breakout)
• (i/p harness, behind center of dash)
• (right side of dash) g201
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse/relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c ctrl
• A/c disable
• A/c enable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c switch
• Air temp dr sensor
• Aux fan ctrl
• Battery
• Blower fuse 3 50a
• Blower motor
• Blower resistor (under right side of dash, on heater housing)
• Blower switch
• Center
• Defogger element
• Diode
• Front mode door motor (under dash on heater- a/c case)
• Front temperature door motor (under dash on heater- a/c case)
• Fuse block
• G120 (right side of engine)
• G202 (behind left side of dash)
• Ground
• Heater and a/c control module
• High blower relay (under dash on top of heater-a/c case)
• Hot at all times
• Hot in run
• Hot in run or start
• Htr-a/c fuse 12 25a
• Ign 1 fuse 10a
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Pnk
• Powertrain control module (left rear of engine compt)
• Rear defogger system
• Recirculation door motor (under dash on heater- a/c case)
• Red
• S107
• S110
• S147 (engine harn, 4 cm from starter motor breakout)
• S185
• S186
• S212 (i/p harn, behind center of dash)
• S243
• S244
• S268
• S298
• Tan
• Underhood fuse-relay

6.5L (VIN S), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Compressor Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, near diode)
• 30 cm from ebcm breakout)
• A/c comp fuse 10a
• A/c compressor clutch
• A/c compressor clutch relay (in underhood fuse-relay center)
• A/c compressor cycling switch (in low pressure line, on accumulator)
• A/c control
• A/c disable
• A/c enable
• A/c high pressure cutout switch (on a/c compressor)
• A/c low pressure cutout switch (on a/c compressor)
• A/c switch
• Aux fan ctrl
• Blower switch
• Diode
• Fuse block
• G120 (right side of engine)
• Hot in run
• Hot in run or start
• Htr a/c fuse 12 25a
• Hvac control module
• Ign 1 fuse 10a
• Ignition
• Off
• Pnk
• Powertrain control module (left rear of engine compt)
• Recirculation door motor (under dash, on heater- a/c case)
• S185
• S186
• S268 (i/p harn, behind center of dash)
• Underhood fuse-relay center

Heater Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Heater Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (hvac harn, 8 cm from recirc door breakout) s244
• (i/p harn, 24 cm from i/p cluster breakout)
• (right side of dash) g201
• Air temp dr sensor
• Battery
• Blower fuse 3 50a
• Blower motor (under right side of dash)
• Blower resistor (on blower motor housing)
• Blower switch
• Defogger element
• Front mode door motor (on front a/c-heater housing)
• Front temperature door motor (on front a/c-heater housing)
• Fuse block
• G202 (behind left side of dash)
• Ground
• High blower relay (on top of front a/c- heater blower housing)
• Hot at all times
• Hot in run
• Htr-a/c fuse 12 25a
• Hvac control module
• Ignition
• Illumination
• Interior lights system
• Mode signal
• Off
• Rear defogger system
• Recirc ctrl
• Recirculation door motor (on front a/c-heater housing)
• Red
• S110 (engine harness, near ebcm breakout)
• S243 (hvac harn, 4 cm from recirc door breakout)
• S268 (i/p harness, behind center of dash)
• S298
• Tan
• Underhood fuse-relay center

ANTI-LOCK BRAKES

5.0L

5.0L (VIN M), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (engine harn, 6.5 cm from underhood fuse relay center)
• (engine harn, near ebcm break- out)
• (engine harn, near tail- lamp breakout)
• (left side of dash) data link connector
• (right lower front of engine)
• 4wd sw input
• 4wd telltale feed
• Abs fuse 60a
• Abs ind
• Abs lamp control
• Brake fuse 18 10a
• Brake ind
• Brake sw input
• Brake sw output
• Daytime running lamps module (left side of dash)
• Ebcm ground
• Electronic brake control module (left side of engine compt)
• G119
• Gauges fuse 4 10a
• Hot at all times
• Hot in run
• Hot in run, bulb test or start
• I/p fuse block
• Ign
• Ind out
• Instrument cluster
• Left front wheel speed sensor
• Lft frt sensor (+)
• Lft frt sensor (-)
• Pnk
• Pump motor ground
• Pump motor power
• Red
• Right front wheel speed sensor
• Rt frt sensor (+)
• Rt frt sensor (-)
• S107
• S111
• S150
• S151
• S152
• S213
• Serial data line
• Tan
• Tcc/ stoplamp switch (top of brake pedal)
• Underhood fuse-relay center
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left side of transmission/ transfer case)
• Vehicle speed sig
• Vss (+)
• Vss (-)
• Vss sig

5.7L

5.7L (VIN R), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (engine harn, 6.5 cm from underhood fuse relay center)
• (engine harn, near ebcm break- out)
• (engine harn, near tail- lamp breakout)
• (left side of dash) data link connector
• (right lower front of engine)
• 4wd sw input
• 4wd telltale feed
• Abs fuse 60a
• Abs ind
• Abs lamp control
• Brake fuse 18 10a
• Brake ind
• Brake sw input
• Brake sw output
• Daytime running lamps module (left side of dash)
• Ebcm ground
• Electronic brake control module (left side of engine compt)
• G119
• Gauges fuse 4 10a
• Hot at all times
• Hot in run
• Hot in run, bulb test or start
• I/p fuse block
• Ign
• Ind out
• Instrument cluster
• Left front wheel speed sensor
• Lft frt sensor (+)
• Lft frt sensor (-)
• Pnk
• Pump motor ground
• Pump motor power
• Red
• Right front wheel speed sensor
• Rt frt sensor (+)
• Rt frt sensor (-)
• S107
• S111
• S150
• S151
• S152
• S213
• Serial data line
• Tan
• Tcc/ stoplamp switch (top of brake pedal)
• Underhood fuse-relay center
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left side of transmission/ transfer case)
• Vehicle speed sig
• Vss (+)
• Vss (-)
• Vss sig

6.5L

6.5L (VIN F), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (engine harn, 4 cm from i/p breakout)
• (engine harness, 13 cm in ebcm breakout)
• (left side of dash) data link connector
• (right front of engine block)
• 4wd input
• 4wd sw input
• A/t only
• Abs fuse 60a
• Abs ind
• Abs lamp control
• Brake fuse 18 10a
• Brake ind
• Brake lamp control
• Brake pressure warning switch
• Brake sw input
• Daytime running lamps module (behind left side of dash)
• Diode 1 (underhood fuse/relay center)
• Ebcm ground
• Electronic brake control module (left side of engine compt)
• Front axle actuator (right front of drive axle)
• G120
• Gauges fuse 4 10a
• Hot at all times
• Hot in run
• Hot in run or start
• I/p fuse block
• Ign
• Instrument cluster
• Left front wheel speed sensor
• Lft frt sensor (+)
• Lft frt sensor (-)
• Pnk
• Pump motor ground
• Pump motor power
• Red
• Right front wheel speed sensor
• Rt frt sensor (+)
• Rt frt sensor (-)
• S107
• S111 (engine harn, near ebcm breakout)
• S150
• S152
• S157
• S213
• Serial data line
• Serial data signal
• Tan
• Underhood fuse-relay center
• Vehicle speed sensor buffer (behind right side of dash)
• Vss sig
• Vss sig out

6.5L (VIN S), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (engine harn, 4 cm from i/p breakout)
• (engine harness, 13 cm in ebcm breakout)
• (left side of dash) data link connector
• (right front of engine block)
• 4wd input
• 4wd sw input
• A/t only
• Abs fuse 60a
• Abs ind
• Abs lamp control
• Brake fuse 18 10a
• Brake ind
• Brake lamp control
• Brake pressure warning switch
• Brake sw input
• Daytime running lamps module (behind left side of dash)
• Diode 1 (underhood fuse/relay center)
• Ebcm ground
• Electronic brake control module (left side of engine compt)
• Front axle actuator (right front of drive axle)
• G120
• Gauges fuse 4 10a
• Hot at all times
• Hot in run
• Hot in run or start
• I/p fuse block
• Ign
• Instrument cluster
• Left front wheel speed sensor
• Lft frt sensor (+)
• Lft frt sensor (-)
• Pnk
• Pump motor ground
• Pump motor power
• Red
• Right front wheel speed sensor
• Rt frt sensor (+)
• Rt frt sensor (-)
• S107
• S111 (engine harn, near ebcm breakout)
• S150
• S152
• S157
• S213
• Serial data line
• Serial data signal
• Tan
• Underhood fuse-relay center
• Vehicle speed sensor buffer (behind right side of dash)
• Vss sig
• Vss sig out

7.4L

7.4L (VIN J), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Anti-lock Brake Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (engine harn, 6.5 cm from underhood fuse relay center)
• (engine harn, near ebcm break- out)
• (engine harn, near tail- lamp breakout)
• (left side of dash) data link connector
• (right lower front of engine)
• 4wd sw input
• 4wd telltale feed
• Abs fuse 60a
• Abs ind
• Abs lamp control
• Brake fuse 18 10a
• Brake ind
• Brake sw input
• Brake sw output
• Daytime running lamps module (left side of dash)
• Ebcm ground
• Electronic brake control module (left side of engine compt)
• G119
• Gauges fuse 4 10a
• Hot at all times
• Hot in run
• Hot in run, bulb test or start
• I/p fuse block
• Ign
• Ind out
• Instrument cluster
• Left front wheel speed sensor
• Lft frt sensor (+)
• Lft frt sensor (-)
• Pnk
• Pump motor ground
• Pump motor power
• Red
• Right front wheel speed sensor
• Rt frt sensor (+)
• Rt frt sensor (-)
• S107
• S111
• S150
• S151
• S152
• S213
• Serial data line
• Tan
• Tcc/ stoplamp switch (top of brake pedal)
• Underhood fuse-relay center
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left side of transmission/ transfer case)
• Vehicle speed sig
• Vss (+)
• Vss (-)
• Vss sig

ANTI-THEFT

Anti-theft Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Anti-theft Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (i/p harn, 5 cm from dlc breakout)
• (top front of engine)
• 12v
• 12v reg
• 5 volt ref
• Data link connector (dlc) (left side of dash)
• Electronic power steering system
• Engine controls system
• Evo sol feed
• Evo sol out
• Evo/passlock module (near dash auxiliary storage compartment)
• G134
• Gauges fuse 4 10a
• Grd
• Hot at all times
• Hot in run or start
• I/p fuse block
• Ign
• Instrument cluster
• Nca
• Passlock sensor (in steering column, near lock cylinder)
• Passlock sig
• Passlock signal
• Pnk
• Resistor (10 ohms)
• S213
• S215
• S280
• Sec ind out
• Sec/strg fuse 21 10a
• Security indicator
• Sens ret
• Sensor grd
• Serial data
• Steering handwheel speed sensor (sensor ground)
• Vss
• Wheel pos sig

COMPUTER DATA LINES

Computer Data Lines for GMC Cab & Chassis C1998 2500

List of elements for Computer Data Lines for GMC Cab & Chassis C1998 2500:

• 13 cm from ebcm breakout)
• Automatic transfer case control module (behind left side of dash)
• Aux pwr fuse 7 25a
• Data clss
• Data clss 2
• Data link connector (under left side of dash, left of steering column)
• Diesel
• Dlc control
• Electronic brake control module (on left side of engine compt)
• Electronic variable orifice/passlock control module (under center of dash)
• G131 (near thermostat housing)
• G202 (behind left side of dash)
• Gasoline
• Hot at all times
• I/p fuse block
• Inflatable restraint sensing and diagnostic module (under driver's seat carpet)
• Powertrain control module (behind right side of dash, near blower motor)
• Prog enable
• Radio
• Remote control door lock receiver (behind center of dash)
• S204
• S215
• S272
• S280 (dash harness, approx 5 cm from dlc breakout)
• Serial data
• Tan
• Transfer case control module (under dash, on steering column support bracket)
• Uart data
• Vehicle control module (on left side of engine compt)

COOLING FAN

5.0L

5.0L (VIN M), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (fwd lamps harn, 5 cm from right headlamp breakout)
• (in underhood fuse/relay center)
• (right front of engine compartment)
• A/c comp fuse 10a
• Aux fan ctrl
• Aux fan fuse 30a
• Auxiliary cooling fan motor
• Auxiliary cooling fan relay
• Fan req
• G101
• Heater and a/c control module
• Hot at all times
• Hot in run or start
• Recirculation door motor (on a/c- heater housing)
• Red
• Relay ctrl
• S128
• S212 (i/p harn, 8 cm from radio breakout)
• Underhood fuse-relay center
• Vehicle control module (left rear of engine compt)

5.7L

5.7L (VIN R), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (fwd lamps harn, 5 cm from right headlamp breakout)
• (in underhood fuse/relay center)
• (right front of engine compartment)
• A/c comp fuse 10a
• Aux fan ctrl
• Aux fan fuse 30a
• Auxiliary cooling fan motor
• Auxiliary cooling fan relay
• Fan req
• G101
• Heater and a/c control module
• Hot at all times
• Hot in run or start
• Recirculation door motor (on a/c- heater housing)
• Red
• Relay ctrl
• S128
• S212 (i/p harn, 8 cm from radio breakout)
• Underhood fuse-relay center
• Vehicle control module (left rear of engine compt)

7.4L

7.4L (VIN J), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Cooling Fan Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (fwd lamps harn, 5 cm from right headlamp breakout)
• (in underhood fuse/relay center)
• (right front of engine compartment)
• A/c comp fuse 10a
• Aux fan ctrl
• Aux fan fuse 30a
• Auxiliary cooling fan motor
• Auxiliary cooling fan relay
• Fan req
• G101
• Heater and a/c control module
• Hot at all times
• Hot in run or start
• Recirculation door motor (on a/c- heater housing)
• Red
• Relay ctrl
• S128
• S212 (i/p harn, 8 cm from radio breakout)
• Underhood fuse-relay center
• Vehicle control module (left rear of engine compt)

CRUISE CONTROL

5.0L

5.0L (VIN M), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (i/p harn, 20 cm from cluster breakout)
• (i/p harn, 20 cm from heater/ a/c breakout)
• (i/p harn, left rear of engine compt)
• (i/p harness, 6 cm from steering column harness breakout)
• 4000 pulses/mile
• A/t
• A12
• A13
• A14
• A15
• Brake fuse 18 10a
• Clutch pedal switch (top of clutch pedal)
• Cruise control module (left rear of engine compartment)
• Cruise control switch
• Cruise fuse 6 10a
• Cruise on input
• Cruise status
• Disengage input
• G120 (right side of engine)
• Ground
• Hot at all times
• Hot in run
• I/p fuse block
• Ignition
• M/t
• Off
• R/a
• Resume/accel input
• S/c
• S153
• S215
• S220
• S221
• S222
• S299
• Set/coast input
• Stop/haz fuse 1 20a
• Stoplamp switch (top of brake pedal)
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed input
• Vehicle speed sensor (vss) (left side of transmission)
• Vss return
• Vss signal

5.7L

5.7L (VIN R), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (i/p harn, 20 cm from cluster breakout)
• (i/p harn, 20 cm from heater/ a/c breakout)
• (i/p harn, left rear of engine compt)
• (i/p harness, 6 cm from steering column harness breakout)
• 4000 pulses/mile
• A/t
• A12
• A13
• A14
• A15
• Brake fuse 18 10a
• Clutch pedal switch (top of clutch pedal)
• Cruise control module (left rear of engine compartment)
• Cruise control switch
• Cruise fuse 6 10a
• Cruise on input
• Cruise status
• Disengage input
• G120 (right side of engine)
• Ground
• Hot at all times
• Hot in run
• I/p fuse block
• Ignition
• M/t
• Off
• R/a
• Resume/accel input
• S/c
• S153
• S215
• S220
• S221
• S222
• S299
• Set/coast input
• Stop/haz fuse 1 20a
• Stoplamp switch (top of brake pedal)
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed input
• Vehicle speed sensor (vss) (left side of transmission)
• Vss return
• Vss signal

6.5L

6.5L (VIN F), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, 4 cm from i/p harness breakout)
• (i/p harn, 12 cm from steering column breakout)
• (i/p harn, 6 cm from steering column breakout)
• A/t
• A11
• A12
• A13
• A14
• A15
• B10
• B11
• Brake fuse 18 10a
• Clutch pedal switch (top of clutch pedal)
• Cruise fuse 6 10a
• Cruise on input
• D10
• Disengage input
• Fuse block
• Hot at all times
• Hot in run
• M/t
• Multifunction lever
• Off
• Powertrain control module (pcm) (right side of dash)
• R/a
• Resume/accel input
• S/c
• S220
• S299
• Set/coast input
• Stop/haz fuse 1 20a
• Tcc/stoplamp switch (top of brake pedal)
• Vehicle speed sensor (vss) buffer (behind right side of dash)
• Vss return

6.5L (VIN S), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (engine harn, 4 cm from i/p harness breakout)
• (i/p harn, 12 cm from steering column breakout)
• (i/p harn, 6 cm from steering column breakout)
• A/t
• A11
• A12
• A13
• A14
• A15
• B10
• B11
• Brake fuse 18 10a
• Clutch pedal switch (top of clutch pedal)
• Cruise fuse 6 10a
• Cruise on input
• D10
• Disengage input
• Fuse block
• Hot at all times
• Hot in run
• M/t
• Multifunction lever
• Off
• Powertrain control module (pcm) (right side of dash)
• R/a
• Resume/accel input
• S/c
• S220
• S299
• Set/coast input
• Stop/haz fuse 1 20a
• Tcc/stoplamp switch (top of brake pedal)
• Vehicle speed sensor (vss) buffer (behind right side of dash)
• Vss return

7.4L

7.4L (VIN J), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Cruise Control Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (i/p harn, 20 cm from cluster breakout)
• (i/p harn, 20 cm from heater/ a/c breakout)
• (i/p harn, left rear of engine compt)
• (i/p harness, 6 cm from steering column harness breakout)
• 4000 pulses/mile
• A/t
• A12
• A13
• A14
• A15
• Brake fuse 18 10a
• Clutch pedal switch (top of clutch pedal)
• Cruise control module (left rear of engine compartment)
• Cruise control switch
• Cruise fuse 6 10a
• Cruise on input
• Cruise status
• Disengage input
• G120 (right side of engine)
• Ground
• Hot at all times
• Hot in run
• I/p fuse block
• Ignition
• M/t
• Off
• R/a
• Resume/accel input
• S/c
• S153
• S215
• S220
• S221
• S222
• S299
• Set/coast input
• Stop/haz fuse 1 20a
• Stoplamp switch (top of brake pedal)
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed input
• Vehicle speed sensor (vss) (left side of transmission)
• Vss return
• Vss signal

DEFOGGERS

Defogger Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Defogger Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (utility only)
• (w/ heated mirrors)
• C222
• Convenience center (under left side of dash)
• G201 (right side of dash)
• G202 (behind left side of dash)
• G305 (right "b" pillar)
• G415 (frame ground, rear of vehicle)
• Heated mirror relay (on convenience center)
• Heater and a/c control switch
• Hot in run
• Hot in run or start
• Htr-a/c fuse 12 25a
• I/p fuse block
• Left cargo door contactor
• Left heated mirror
• Left outside rear view mirror
• Left rear cargo door defogger grid
• Mirrors fuse 10a
• Nca
• Nca a
• Pick-up w/ extended or crew cab
• Rear defogger switch
• Rear window defogger grid
• Right cargo door contactor
• Right heated mirror
• Right rear cargo door defogger grid
• Rr-defog fuse 30a
• S218
• S251
• S259
• S268
• S410
• S425 (body harn., approx 11 cm from lr speaker breakout)
• S506 (inside power outside rear view mirror harn., 7 cm from power outside rear view mirror)
• Solid state time delay relay
• Suburban/utility w/ liftgate
• Suburban/utility w/o liftgate
• Underhood fuse/relay center

ELECTRONIC POWER STEERING

Electronic Power Steering Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Electronic Power Steering Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (diesel: i/p harness, approximately 8 cm from instrument cluster breakout, toward radio connectors breakout) (gasoline: i/p harness, approximately 12 cm from instrument cluster breakout toward radio connectors breakout)
• (front top of engine) g134
• (i/p harness, approximately 40 cm from instrument cluster breakout)
• (i/p harness, approximately 5 cm from dlc breakout)
• (right top of cylinder head) g120
• 5 volt ref
• Battery
• Dash fuse block (under left side of dash)
• Data
• Data link connector (dlc) (under left side of dash, left of steering column)
• Diesel
• Electronic variable orifice (evo)/passlock control module (under center of dash)
• Evo feed
• Evo solenoid out
• Gas
• Gauges fuse 4 10a
• Ground
• Hot at all times
• Hot in run or start
• Ignition
• Pnk
• S213
• S215
• S221
• S280
• Security/strg fuse 21 20a
• Sensor return
• Steering assist control solenoid (part of power steering pump)
• Steering handwheel speed sensor (on steering column, near firewall)
• Steering wheel posit signal
• Sws posit sig
• Vehicle control module (on left side of engine compartment)
• Vehicle speed sensor buffer (behind right side of dash)
• Volt ref
• Vss sig out
• Vss signal input

ENGINE PERFORMANCE

5.0L

5.0L (VIN M), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500:

• (attached to right rear of throttle body) idle air control (iac) valve
• (bottom front of engine near, crank pulley) crankshaft position sensor
• (top right side of engine) evaporative emission canister purge valve
• 1-2 shift sol ctrl
• 2-3 shift sol ctrl
• 3-2 shift sol ctrl
• Air pump rel ctrl
• Cam posit sens sig
• Camshaft position sensor (inside distributor)
• Crank posit sens sig
• Ect sens sig
• Egr posit sig
• Fuel gauge lvl
• Fuel tank press sens
• G119 (right front of engine block)
• Heated oxygen sensor (bank 1 sensor 1) (in exhaust pipe in front of left catalytic converter)
• Heated oxygen sensor (bank 1 sensor 3) (in exhaust pipe in back of right catalytic converter)
• Heated oxygen sensor (bank 2 sensor 1) (in exhaust pipe in front of right catalytic converter)
• Ho2s low
• Ho2s sig
• Iat sens sig
• Idle air ctrl (iac) a hi
• Idle air ctrl (iac) b lo
• Ign feed
• Ignition
• Inj 1 ctrl
• Inj 2 ctrl
• Inj 3 ctrl
• Inj 4 ctrl
• Inj 5 ctrl
• Inj 6 ctrl
• Inj 7 ctrl
• Inj 8 ctrl
• Knock sens sig
• Knock sensor (ks) (right side of engine block, below exhaust manifold, forward of starter)
• Map sens input
• Mass air flow sens sig
• Nca
• Pnk
• Pnk c ignition feed
• S148
• S149
• S162
• Sens rtn
• Sens sig
• Sensor return
• Tan
• Tcc pwm sol ctrl
• Tcc sol ctrl
• Temp sens input
• Throttle posit sens
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed sensor (left side of transmission, left side of transfer case)
• Vent ctlr
• Vss rtn
• Vss sig
• Vss signal

5.0L (VIN M), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500:

• 1-2 shift sol
• 2-3 shift sol
• 3-2 shift sol
• Air injection reaction (secondary) pump clutch (on front of pump)
• Air injection reaction relay (underhood fuse/ relay center)
• Automatic transmission
• Aux-b fuse 30a stud-b
• Ecm1 fuse 20a
• Eng1 k7
• Evaporative emissions (evap) canister vent valve (left side of engine compt)
• Exhaust gas recirculation (egr) valve (front of engine near thermostat housing)
• Fluid pressure (tfp) manual valve position switch
• Fluid temperature sensor (internal)
• Fuel inj 1
• Fuel inj 2
• Fuel inj 3
• Fuel inj 4
• Fuel inj 5
• Fuel inj 6
• Fuel inj 7
• Fuel inj 8
• Fuse 20a l8
• G119 (right front of engine block)
• Heated oxygen sensor (bank 1 sensor 2) (in exhaust pipe in back of left catalytic converter)
• Hot at all times
• Hot in run & start
• Ignition
• Nca
• Note: fuel injectors are located on top of engine, in intake manifold
• Pnk
• Pnk pnk pnk tan red
• Pressure control solenoid valve
• Red
• S (w/4l80e trans)
• S104
• S108
• S147
• S161
• S166 (eng harn, 18 cm from ebcm breakout)
• Tcc solenoid
• Torque convertor clutch pulse width modulation solenoid
• U (w/4l60e trans)
• Under hood fuse-relay center
• W/4l60e 4-speed trans only

5.0L (VIN M), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500:

• (eng harn, approx 17 cm from breakout to egr valve) s106
• (engine harn, approx 16 cm from breakout to egr valve)
• (engine harn, approx 27 cm in breakout to egr valve)
• (inside left frame rail, near rear crossmember) g415
• (right top of cylinder head) g120
• (taillamp extension harn, 6 cm from the fuel pump harn breakout)
• (taillamp extension harness, approx 10 cm from fuel pump balance module breakout)
• Automatic transmission input shaft speed (a/t iss) sensor
• Balance fuel pump (on inside left frame rail near front of rear tank)
• D w/ dual fuel tanks
• Engine coolant temperature sensor (top right front of engine, near thermostat housing)
• F7 ign e fuse 10a g8
• Fuel pump & sender (in fuel tank)
• Fuel pump balance module (inside left side of frame rail)
• Fuel pump balance relay (on fuel pump balance module)
• Fuel pump/ oil pressure switch (top center rear of engine, behind distributor)
• Fuel tank pressure sensor (calif only) (in fuel tank)
• Fuel tanks
• Gauges fuse 4 10a
• Hot in off, run or start
• Hot in run or start
• I/p fuse block
• Ignition
• Input fuel gauge
• Input oil gauge
• Input tachometer
• Instrument cluster
• Intake air temperature sensor (in air intake duct)
• M/t only
• Map sensor pressure (map) sensor (top right of engine, near fuel injectors)
• Mass air flow sensor (in air intake duct)
• Output to gauge c2
• Pnk
• Pnk a
• Pnk pnk tan red
• Primary tank fuel lvl sig
• Relay ctrl
• S100
• S103
• S213
• S231
• S232
• S315
• S318
• S319
• S324
• S430
• Service engine soon indicator
• Speedometer input
• Tan
• Tan a
• Throttle position sensor (on throttle body assembly)
• Trans fuse 20 10a
• Underhood fuse-relay center pnk
• Upshift lamp
• W/ dual fuel tanks
• W/ dual w/o dual fuel tanks
• W/o dual fuel tanks

5.0L (VIN M), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, 7 cm from ebcm breakout)
• (engine harness, approx 13 cm from s150
• (engine harness, approx 7 cm from ebcm breakout)
• (i/p harn, 20 cm from inflatable restraint i/p module switch breakout)
• (i/p harn, harness, 13 cm from left engine grommet)
• (i/p harness, approx 40 cm from instrument cluster breakout)
• (or
• (right top of cyl head) g120
• 4wd input
• 5v ref voltage
• A/c comp enable rel
• A/c request signal
• A/t
• Air conditioning system
• Air inlet vlv mtr ctlr
• Aux fan relay
• Brake sw input
• Brake switch input
• Check eng lp ctrl
• Clutch pedal position (cpp) switch (at top of clutch pedal)
• Cooling fans system
• Cpp sw input
• Cruise control module (left rear of engine compartment, on firewall)
• Cruise ctrl sig eng
• Data link connector (under left side of dash)
• Distributor
• Ebcm breakout)
• Egr vlv feed
• Egr vlv ground
• Electronic brake control module (ebcm) (on left side of engine compartment)
• Est output sig
• Evap can purge vlv
• Evo/passlock steering control module (center of dash)
• F11 ecmb fuse 20a
• Force motor feed
• Force motor return
• Four whl dr sig
• Four whl dr sig lo
• Fuel a pump prime connector
• Fuel level input
• Fuel pump relay
• Fuel pump rly ctrl
• G12
• G120 (right top of cylinder head)
• Ground
• High voltage coil wire
• Hot at all times
• Hot in run
• I/p fuse block
• Ign coil out
• Ign input
• Ign timing sig.
• Ignition
• Ignition coil (top left rear of engine)
• Ignition coil driver (left rear side of engine)
• Ignition feed
• M/t
• M4 brake fuse 18 10a n3
• Pnk
• Pnk a
• Pressure switch input
• Radio
• Red
• S101
• S103
• S111 (engine harness, approx 10 cm from ebcm breakout)
• S151
• S152
• S153
• S221
• Sensor ground
• Sensor return
• Serial data sig
• Shift ind lp out
• Speed sensor
• Speed sensor input
• Stoplamp switch (top of brake pedal)
• Stoplamp/ clutch switch input
• Switch signal
• Trans input speed rtn
• Trans input speed sig
• Transfer case control module (under dash, on steering column support bracket)
• Transfer case switch (left top of transfer case)
• Transmissions system (four wheel drive indicator circuit)
• Underhood fuse- relay center
• Vcm sig
• Vehicle control module (vcm) (left side of engine compt)
• Vss input
• Vss sig out

5.7L

5.7L (VIN R), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500:

• (attached to right rear of throttle body) idle air control (iac) valve
• (bottom front of engine near, crank pulley) crankshaft position sensor
• (top right side of engine) evaporative emission canister purge valve
• 1-2 shift sol ctrl
• 2-3 shift sol ctrl
• 3-2 shift sol ctrl
• Air pump rel ctrl
• Cam posit sens sig
• Camshaft position sensor (inside distributor)
• Crank posit sens sig
• Ect sens sig
• Egr posit sig
• Fuel gauge lvl
• Fuel tank press sens
• G119 (right front of engine block)
• Heated oxygen sensor (bank 1 sensor 1) (in exhaust pipe in front of left catalytic converter)
• Heated oxygen sensor (bank 1 sensor 3) (in exhaust pipe in back of right catalytic converter)
• Heated oxygen sensor (bank 2 sensor 1) (in exhaust pipe in front of right catalytic converter)
• Ho2s low
• Ho2s sig
• Iat sens sig
• Idle air ctrl (iac) a hi
• Idle air ctrl (iac) b lo
• Ign feed
• Ignition
• Inj 1 ctrl
• Inj 2 ctrl
• Inj 3 ctrl
• Inj 4 ctrl
• Inj 5 ctrl
• Inj 6 ctrl
• Inj 7 ctrl
• Inj 8 ctrl
• Knock sens sig
• Knock sensor (ks) (right side of engine block, below exhaust manifold, forward of starter)
• Map sens input
• Mass air flow sens sig
• Nca
• Pnk
• Pnk c ignition feed
• S148
• S149
• S162
• Sens rtn
• Sens sig
• Sensor return
• Tan
• Tcc pwm sol ctrl
• Tcc sol ctrl
• Temp sens input
• Throttle posit sens
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed sensor (left side of transmission, left side of transfer case)
• Vent ctlr
• Vss rtn
• Vss sig
• Vss signal

5.7L (VIN R), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500:

• 1-2 shift sol
• 2-3 shift sol
• 3-2 shift sol
• Air injection reaction (secondary) pump clutch (on front of pump)
• Air injection reaction relay (underhood fuse/ relay center)
• Automatic transmission
• Aux-b fuse 30a stud-b
• Ecm1 fuse 20a
• Eng1 k7
• Evaporative emissions (evap) canister vent valve (left side of engine compt)
• Exhaust gas recirculation (egr) valve (front of engine near thermostat housing)
• Fluid pressure (tfp) manual valve position switch
• Fluid temperature sensor (internal)
• Fuel inj 1
• Fuel inj 2
• Fuel inj 3
• Fuel inj 4
• Fuel inj 5
• Fuel inj 6
• Fuel inj 7
• Fuel inj 8
• Fuse 20a l8
• G119 (right front of engine block)
• Heated oxygen sensor (bank 1 sensor 2) (in exhaust pipe in back of left catalytic converter)
• Hot at all times
• Hot in run & start
• Ignition
• Nca
• Note: fuel injectors are located on top of engine, in intake manifold
• Pnk
• Pnk pnk pnk tan red
• Pressure control solenoid valve
• Red
• S (w/4l80e trans)
• S104
• S108
• S147
• S161
• S166 (eng harn, 18 cm from ebcm breakout)
• Tcc solenoid
• Torque convertor clutch pulse width modulation solenoid
• U (w/4l60e trans)
• Under hood fuse-relay center
• W/4l60e 4-speed trans only

5.7L (VIN R), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500:

• (eng harn, approx 17 cm from breakout to egr valve) s106
• (engine harn, approx 16 cm from breakout to egr valve)
• (engine harn, approx 27 cm in breakout to egr valve)
• (inside left frame rail, near rear crossmember) g415
• (right top of cylinder head) g120
• (taillamp extension harn, 6 cm from the fuel pump harn breakout)
• (taillamp extension harness, approx 10 cm from fuel pump balance module breakout)
• Automatic transmission input shaft speed (a/t iss) sensor
• Balance fuel pump (on inside left frame rail near front of rear tank)
• D w/ dual fuel tanks
• Engine coolant temperature sensor (top right front of engine, near thermostat housing)
• F7 ign e fuse 10a g8
• Fuel pump & sender (in fuel tank)
• Fuel pump balance module (inside left side of frame rail)
• Fuel pump balance relay (on fuel pump balance module)
• Fuel pump/ oil pressure switch (top center rear of engine, behind distributor)
• Fuel tank pressure sensor (calif only) (in fuel tank)
• Fuel tanks
• Gauges fuse 4 10a
• Hot in off, run or start
• Hot in run or start
• I/p fuse block
• Ignition
• Input fuel gauge
• Input oil gauge
• Input tachometer
• Instrument cluster
• Intake air temperature sensor (in air intake duct)
• M/t only
• Map sensor pressure (map) sensor (top right of engine, near fuel injectors)
• Mass air flow sensor (in air intake duct)
• Output to gauge c2
• Pnk
• Pnk a
• Pnk pnk tan red
• Primary tank fuel lvl sig
• Relay ctrl
• S100
• S103
• S213
• S231
• S232
• S315
• S318
• S319
• S324
• S430
• Service engine soon indicator
• Speedometer input
• Tan
• Tan a
• Throttle position sensor (on throttle body assembly)
• Trans fuse 20 10a
• Underhood fuse-relay center pnk
• Upshift lamp
• W/ dual fuel tanks
• W/ dual w/o dual fuel tanks
• W/o dual fuel tanks

5.7L (VIN R), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, 7 cm from ebcm breakout)
• (engine harness, approx 13 cm from s150
• (engine harness, approx 7 cm from ebcm breakout)
• (i/p harn, 20 cm from inflatable restraint i/p module switch breakout)
• (i/p harn, harness, 13 cm from left engine grommet)
• (i/p harness, approx 40 cm from instrument cluster breakout)
• (or
• (right top of cyl head) g120
• 4wd input
• 5v ref voltage
• A/c comp enable rel
• A/c request signal
• A/t
• Air conditioning system
• Air inlet vlv mtr ctlr
• Aux fan relay
• Brake sw input
• Brake switch input
• Check eng lp ctrl
• Clutch pedal position (cpp) switch (at top of clutch pedal)
• Cooling fans system
• Cpp sw input
• Cruise control module (left rear of engine compartment, on firewall)
• Cruise ctrl sig eng
• Data link connector (under left side of dash)
• Distributor
• Ebcm breakout)
• Egr vlv feed
• Egr vlv ground
• Electronic brake control module (ebcm) (on left side of engine compartment)
• Est output sig
• Evap can purge vlv
• Evo/passlock steering control module (center of dash)
• F11 ecmb fuse 20a
• Force motor feed
• Force motor return
• Four whl dr sig
• Four whl dr sig lo
• Fuel a pump prime connector
• Fuel level input
• Fuel pump relay
• Fuel pump rly ctrl
• G12
• G120 (right top of cylinder head)
• Ground
• High voltage coil wire
• Hot at all times
• Hot in run
• I/p fuse block
• Ign coil out
• Ign input
• Ign timing sig.
• Ignition
• Ignition coil (top left rear of engine)
• Ignition coil driver (left rear side of engine)
• Ignition feed
• M/t
• M4 brake fuse 18 10a n3
• Pnk
• Pnk a
• Pressure switch input
• Radio
• Red
• S101
• S103
• S111 (engine harness, approx 10 cm from ebcm breakout)
• S151
• S152
• S153
• S221
• Sensor ground
• Sensor return
• Serial data sig
• Shift ind lp out
• Speed sensor
• Speed sensor input
• Stoplamp switch (top of brake pedal)
• Stoplamp/ clutch switch input
• Switch signal
• Trans input speed rtn
• Trans input speed sig
• Transfer case control module (under dash, on steering column support bracket)
• Transfer case switch (left top of transfer case)
• Transmissions system (four wheel drive indicator circuit)
• Underhood fuse- relay center
• Vcm sig
• Vehicle control module (vcm) (left side of engine compt)
• Vss input
• Vss sig out

6.5L

6.5L (VIN F), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500:

• (bottom front of engine, near crank pulley) crankshaft position (ckp) sensor
• (engine harn, 31 cm from taillamp harn breakout)
• (engine harness)
• (i/p harness)
• (i/p harness, approx 16 cm into i/p cluster breakout)
• (right top of cylinder head) g119
• (top of engine,
• (top right front of engine) engine coolant temperature (ect) sensor
• 12v
• 3/2 shift sol
• 4wd signal
• 5 volt ref
• 5 vref
• 5v ref volt
• A/c request sig
• A/c system
• A/t fluid pressure (tfp) manual valve position switch
• A10
• A11 3 mode cruise a12
• Anti-lock brakes system
• App 1 sig
• App 2 sig
• App 3 sig
• Automatic transmission
• Automatic transmission input shaft speed (a/t iss) sensor (left side of transmission near front)
• B10
• B11
• B12
• Baro sensor input
• Boost pressure sensor
• Brake sw in
• Brake switch input
• C10
• C11
• C12
• C13
• C14
• C15
• C16
• Cam posit sens sig rtn
• Camshaft posit sens
• Closure gnd
• Cruise control
• Cruise ctrl sw engage
• Cruise eng sw retard
• D10
• D11
• D12
• D13
• D14
• D15
• D16
• Ect temp sens in
• Engine crank sens input
• Exhaust gas recirculation (egr) control/ barometric (baro) pressure sensor (left side of firewall, near wiper motor)
• Force mtr hi
• Force mtr low
• Fuel pump input
• Fuel pump rly ctrl
• Fuel sol closure (5v sig)
• Fuel temp sens (5v sig)
• Glow plug "wait" lp out
• Glow plug relay
• Ground
• Intake man air temp sens
• Map sens input
• Nca
• Near intake manifold) intake air temperature (iat) sensor
• On/off
• Pnk
• Powertrain control module (pcm) (behind right side of dash, near blower motor)
• Pressure control solenoid valve
• Radio
• Range mode sel a
• Range mode sel b
• Range mode sel c
• Red
• Resume
• S140
• S170
• S199
• S211
• S215
• S230
• Sensor gnd
• Set
• Shift sol a
• Shift sol b
• Switch
• Tan
• Timing stepper mtr (high)
• Timing stepper mtr (low)
• Transmission speed input
• Transmission temp input
• Transmission temperature sensor
• Transmissions system
• Vehicle speed input
• Vehicle speed sensor (on transmission, left rear side)
• Vehicle speed sensor buffer (behind right side of dash)
• Vss hi
• Vss output
• Vss rtn
• Vss sig

6.5L (VIN F), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, approx 4 cm from i/p harness breakout) (a/t) (i/p harn, 20 cm from inflatable restraint i/p module switch breakout) (m/t)
• (engine jumper harness, toward fuel temperature sensor)
• (on inj pump)
• 5 volt ref
• Accelerator pedal position (app) module (part of accelerator pedal)
• Brake switch assembly (at rear of brake pedal support bracket)
• Clutch pedal position (cpp) switch (m/t only) (top of clutch pedal)
• Cmp sig
• D2 trans fuse 20 20a e1
• D8 stop/haz fuse 1 20a c7
• Ecm-1 h7
• Electronic brake control module (on left side of engine compt)
• Engine shutoff solenoid (left front of engine)
• Fuel solenoid (on inj pump, top front of engine)
• Fuel solenoid driver (on inj pump, top front of engine)
• Fuse 20a
• High res sig
• Hot at all times
• Hot in run
• Hot in run or start
• I/p fuse block
• Injection timing stepper motor (top right front of engine)
• M4 brake fuse 18 10a n3
• Nca
• Optical fuel temperature sensor (on fuel inj pump)
• Pnk
• Pnk pnk
• Power distribution system
• Red
• S190
• S198
• S220 (i/p harness, approx 6 cm from steering column breakout)
• S222 (m/t) s152 (a/t)
• S299
• Sens grd
• Tan d
• Underhood fuse-relay center

6.5L (VIN F), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, approx 37 cm from breakout to ebcm) (m/t) (engine harness, approx 31 cm from taillamp harn breakout) (a/t) s100
• (inside left frame rail, below driver's door)
• (right top of cylinder head)
• (right top of cylinder head) g119
• (taillamp extension harness, approx 10 cm from fuel pump balance module breakout)
• Ecm-b fuse 20a
• F11
• Fuel lift pump
• Fuel pump prime connector
• Fuel pump relay (in underhood fuse-relay center)
• Fuel pump/ oil pressure switch and sender (under intake manifold, center of engine)
• G119
• G12
• Gauges fuse 4 10a
• Hot at all times
• Hot in run or start
• I/p fuse block
• Instrument cluster
• Instrument cluster system
• Instrument cluster system (fuel pump balance relay)
• Pnk
• Red
• S101
• S103
• S147
• S213
• S318
• Service engine soon indicator
• Service throttle soon indicator
• Tan
• Underhood fuse-relay center
• Vehicle speed input
• W/dual tanks
• W/o dual tanks
• Wait to start "glow plugs" indicator
• Water in fuel indicator
• Water in-fuel sensor (top center rear of engine)

6.5L (VIN F), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500:

• "serv eng soon" ind
• "serv throttle soon" ind
• (at air intake duct) mass air flow (maf) sensor
• (below dash, near steering column)
• (eng jumper harn, from fuel solenoid driver)
• (engine harness)
• (engine harness, approx 11 cm from i/p harness breakout)
• (engine harness, approx 13 cm into ebcm breakout)
• (right top of cylinder head) g119
• 12v battery (fused)
• 12v battery fused
• 3/2 ctrl out
• A/c enable
• A/c system
• C10
• C11
• C12
• C13
• C14
• C15
• C16
• D10
• D11
• D12
• D13
• D14
• D15
• D16
• Data link connector (dlc)
• Egr sol output
• Egr valve sol putput
• Electronic brake brake control module (ebcm) (on left side of engine compt)
• Eng-i k7
• Engine shutoff sol out
• Exhaust gas recirculation (egr) vent solenoid (top left rear of engine)
• Exhaust gas recirculation egr solenoid (top left rear of engine)
• Fuel heater (top rear of engine)
• Fuel sol module (5 vref)
• Fuel sol module feed
• Fuse 20a
• Fusible link
• Fusible links
• G119 (right top of cylinder head)
• Glow plug 1
• Glow plug 2
• Glow plug 3
• Glow plug 4
• Glow plug 5
• Glow plug 6
• Glow plug 7
• Glow plug 8
• Glow plug output
• Glow plug relay (top left rear of engine)
• Grd
• Ground
• Hot at all times
• Hot in run or start
• Ign
• Ignition
• Maf
• Pcm gnd
• Pnk
• Powertrain control module (pcm) (behind right side of dash, near blower motor)
• Red
• Relay ctrl
• S103
• S108
• S137
• S138
• S147
• S150
• S191
• S269
• Serial data sig
• Shift sol a input
• Shift sol b input
• Signal
• Tan
• Tps 2 ref voltage
• Underhood fuse-relay center
• Wait to start ind
• Wastegate sol
• Wastegate solenoid (top left rear of engine)

6.5L (VIN S), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500:

• (bottom front of engine, near crank pulley) crankshaft position (ckp) sensor
• (engine harn, 31 cm from taillamp harn breakout)
• (engine harness)
• (i/p harness)
• (i/p harness, approx 16 cm into i/p cluster breakout)
• (right top of cylinder head) g119
• (top of engine,
• (top right front of engine) engine coolant temperature (ect) sensor
• 12v
• 3/2 shift sol
• 4wd signal
• 5 volt ref
• 5 vref
• 5v ref volt
• A/c request sig
• A/c system
• A/t fluid pressure (tfp) manual valve position switch
• A10
• A11 3 mode cruise a12
• Anti-lock brakes system
• App 1 sig
• App 2 sig
• App 3 sig
• Automatic transmission
• Automatic transmission input shaft speed (a/t iss) sensor (left side of transmission near front)
• B10
• B11
• B12
• Baro sensor input
• Boost pressure sensor
• Brake sw in
• Brake switch input
• C10
• C11
• C12
• C13
• C14
• C15
• C16
• Cam posit sens sig rtn
• Camshaft posit sens
• Closure gnd
• Cruise control
• Cruise ctrl sw engage
• Cruise eng sw retard
• D10
• D11
• D12
• D13
• D14
• D15
• D16
• Ect temp sens in
• Engine crank sens input
• Exhaust gas recirculation (egr) control/ barometric (baro) pressure sensor (left side of firewall, near wiper motor)
• Force mtr hi
• Force mtr low
• Fuel pump input
• Fuel pump rly ctrl
• Fuel sol closure (5v sig)
• Fuel temp sens (5v sig)
• Glow plug "wait" lp out
• Glow plug relay
• Ground
• Intake man air temp sens
• Map sens input
• Nca
• Near intake manifold) intake air temperature (iat) sensor
• On/off
• Pnk
• Powertrain control module (pcm) (behind right side of dash, near blower motor)
• Pressure control solenoid valve
• Radio
• Range mode sel a
• Range mode sel b
• Range mode sel c
• Red
• Resume
• S140
• S170
• S199
• S211
• S215
• S230
• Sensor gnd
• Set
• Shift sol a
• Shift sol b
• Switch
• Tan
• Timing stepper mtr (high)
• Timing stepper mtr (low)
• Transmission speed input
• Transmission temp input
• Transmission temperature sensor
• Transmissions system
• Vehicle speed input
• Vehicle speed sensor (on transmission, left rear side)
• Vehicle speed sensor buffer (behind right side of dash)
• Vss hi
• Vss output
• Vss rtn
• Vss sig

6.5L (VIN S), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, approx 4 cm from i/p harness breakout) (a/t) (i/p harn, 20 cm from inflatable restraint i/p module switch breakout) (m/t)
• (engine jumper harness, toward fuel temperature sensor)
• (on inj pump)
• 5 volt ref
• Accelerator pedal position (app) module (part of accelerator pedal)
• Brake switch assembly (at rear of brake pedal support bracket)
• Clutch pedal position (cpp) switch (m/t only) (top of clutch pedal)
• Cmp sig
• D2 trans fuse 20 20a e1
• D8 stop/haz fuse 1 20a c7
• Ecm-1 h7
• Electronic brake control module (on left side of engine compt)
• Engine shutoff solenoid (left front of engine)
• Fuel solenoid (on inj pump, top front of engine)
• Fuel solenoid driver (on inj pump, top front of engine)
• Fuse 20a
• High res sig
• Hot at all times
• Hot in run
• Hot in run or start
• I/p fuse block
• Injection timing stepper motor (top right front of engine)
• M4 brake fuse 18 10a n3
• Nca
• Optical fuel temperature sensor (on fuel inj pump)
• Pnk
• Pnk pnk
• Power distribution system
• Red
• S190
• S198
• S220 (i/p harness, approx 6 cm from steering column breakout)
• S222 (m/t) s152 (a/t)
• S299
• Sens grd
• Tan d
• Underhood fuse-relay center

6.5L (VIN S), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harness, approx 37 cm from breakout to ebcm) (m/t) (engine harness, approx 31 cm from taillamp harn breakout) (a/t) s100
• (inside left frame rail, below driver's door)
• (right top of cylinder head)
• (right top of cylinder head) g119
• (taillamp extension harness, approx 10 cm from fuel pump balance module breakout)
• Ecm-b fuse 20a
• F11
• Fuel lift pump
• Fuel pump prime connector
• Fuel pump relay (in underhood fuse-relay center)
• Fuel pump/ oil pressure switch and sender (under intake manifold, center of engine)
• G119
• G12
• Gauges fuse 4 10a
• Hot at all times
• Hot in run or start
• I/p fuse block
• Instrument cluster
• Instrument cluster system
• Instrument cluster system (fuel pump balance relay)
• Pnk
• Red
• S101
• S103
• S147
• S213
• S318
• Service engine soon indicator
• Service throttle soon indicator
• Tan
• Underhood fuse-relay center
• Vehicle speed input
• W/dual tanks
• W/o dual tanks
• Wait to start "glow plugs" indicator
• Water in fuel indicator
• Water in-fuel sensor (top center rear of engine)

6.5L (VIN S), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500:

• "serv eng soon" ind
• "serv throttle soon" ind
• (at air intake duct) mass air flow (maf) sensor
• (below dash, near steering column)
• (eng jumper harn, from fuel solenoid driver)
• (engine harness)
• (engine harness, approx 11 cm from i/p harness breakout)
• (engine harness, approx 13 cm into ebcm breakout)
• (right top of cylinder head) g119
• 12v battery (fused)
• 12v battery fused
• 3/2 ctrl out
• A/c enable
• A/c system
• C10
• C11
• C12
• C13
• C14
• C15
• C16
• D10
• D11
• D12
• D13
• D14
• D15
• D16
• Data link connector (dlc)
• Egr sol output
• Egr valve sol putput
• Electronic brake brake control module (ebcm) (on left side of engine compt)
• Eng-i k7
• Engine shutoff sol out
• Exhaust gas recirculation (egr) vent solenoid (top left rear of engine)
• Exhaust gas recirculation egr solenoid (top left rear of engine)
• Fuel heater (top rear of engine)
• Fuel sol module (5 vref)
• Fuel sol module feed
• Fuse 20a
• Fusible link
• Fusible links
• G119 (right top of cylinder head)
• Glow plug 1
• Glow plug 2
• Glow plug 3
• Glow plug 4
• Glow plug 5
• Glow plug 6
• Glow plug 7
• Glow plug 8
• Glow plug output
• Glow plug relay (top left rear of engine)
• Grd
• Ground
• Hot at all times
• Hot in run or start
• Ign
• Ignition
• Maf
• Pcm gnd
• Pnk
• Powertrain control module (pcm) (behind right side of dash, near blower motor)
• Red
• Relay ctrl
• S103
• S108
• S137
• S138
• S147
• S150
• S191
• S269
• Serial data sig
• Shift sol a input
• Shift sol b input
• Signal
• Tan
• Tps 2 ref voltage
• Underhood fuse-relay center
• Wait to start ind
• Wastegate sol
• Wastegate solenoid (top left rear of engine)

7.4L

7.4L (VIN J), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams (1 of 4) for GMC Cab & Chassis C1998 2500:

• (attached to right rear of throttle body) idle air control (iac) valve
• (bottom front of engine, near crank pulley) crankshaft position sensor
• (engine harness, approx 11 cm into egr valve breakout)
• (right side of engine) evaporative emission canister purge valve
• 1-2 shift sol ctrl
• 2-3 shift sol ctrl
• Air pump relay ctrl
• Cam posit sens sig
• Camshaft position sensor (inside distributor)
• Crank posit sens sig
• Ect sens sig
• Egr posit sig
• Evap sol purge ctrl
• Fuel lvl output
• Fuel tank pressure
• G119 (right front of engine block)
• Heated oxygen sensor (ho2s) (bank 2 sensor 1) (in exhaust pipe in front of left catalytic converter)
• Heated oxygen sensor (ho2s) (bank 2 sensor 2) (in exhaust pipe in back of right catalytic converter)
• Heated oxygen sensor (ho2s) (bank 2 sensor1) (in exhaust pipe in front of right catalytic converter)
• Ho2s high
• Ho2s low
• Iat sens sig
• Idle air ctrl (iac) a hi
• Idle air ctrl (iac) b lo
• Ign feed
• Ignition
• Inj 1 ctrl
• Inj 2 ctrl
• Inj 3 ctrl
• Inj 4 ctrl
• Inj 5 ctrl
• Inj 6 ctrl
• Inj 7 ctrl
• Inj 8 ctrl
• Knock sens sig
• Knock sensor (right side of engine)
• Map sens input
• Mass air flow sens sig
• Nca
• Pnk
• Pnk c ignition feed
• S145
• S148
• S149
• S162
• Sens rtn
• Sens sig
• Sensor return
• Tan
• Tcc sol ctrl
• Temp sens input
• Throttle posit sens
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed sensor (left side of transmission, left side of transfer case)
• Vent ctrl
• Vss rtn
• Vss sig
• Vss signal

7.4L (VIN J), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams (2 of 4) for GMC Cab & Chassis C1998 2500:

• 1-2 shift solenoid
• 2-3 shift solenoid
• Air injection reaction (a.i.r.) pump clutch (front of engine)
• Air injection reaction (a.i.r.) relay (underhood fuse/ relay center)
• Automatic transmission
• Ecm-1 fuse 20a
• Eng-1 k7
• Evaporative emissions (evap) canister vent (left side of eng compt)
• Exhaust gas recirculation (egr) valve (front of engine near thermostat housing)
• Fluid pressure (tfp) manual valve position switch
• Fluid temperature sensor (internal)
• Fuel inj 1
• Fuel inj 2
• Fuel inj 3
• Fuel inj 4
• Fuel inj 5
• Fuel inj 6
• Fuel inj 7
• Fuel inj 8
• Fuse 20a l8
• G119 (right front of engine block)
• Heated oxygen sensor (ho2s) (bank 1 sensor 2) (in exhaust pipe in back of left catalytic converter)
• Hot in run or start
• Ignition
• Nca
• Note: fuel injectors are located on top of engine, in intake manifold
• Pnk
• Pnk pnk pnk tan pnk pnk
• Pressure control solenoid valve
• Red
• S104
• S108
• S147
• S154
• S155
• Tan
• Torque convertor clutch pulse width modulation solenoid
• Under hood fuse-relay center

7.4L (VIN J), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams (3 of 4) for GMC Cab & Chassis C1998 2500:

• (eng harn, 23 cm from ebcm breakout)
• (engine harn, approx 4cm in breakout to egr valve)
• (engine harness, approx 4.5 cm from breakout to egr valve)
• (inside left frame rail, near rear crossmember) g415
• (right front of engine, near thermostat housing) g119
• (right top of cyl head) g120
• (right top of cylinder head) g120
• (taillamp extension harn, 6 cm from fuel pump harn breakout)
• Automatic transmission input shaft speed (a/t iss) sensor
• Balance fuel pump (on inside left frame rail near front of rear tank)
• Convenience center
• Engine coolant temperature sensor (top right front of engine, near thermostat housing)
• Fuel pump and sender (in fuel tank)
• Fuel pump balance module (inside left side of frame rail)
• Fuel pump balance relay (on fuel pump balance module)
• Fuel pump/ oil pressure switch (top left rear of engine, near distributor)
• Fuel tank pressure sensor (in fuel tank)
• Gauges fuse 4 10a
• Hot in off, run or start
• Hot in run or start
• Hot in run, or start
• I/p fuse block
• Ign e fuse 10a
• Ignition
• Input fuel gauge
• Input oil gauge
• Input tachometer
• Instrument cluster
• Intake air temperature sensor (in air intake duct)
• M/t only
• Map sensor (top right of engine, rear of fuel injectors)
• Mass air flow sensor (air intake duct)
• Out to gauge
• Pnk
• Pnk a
• Pnk pnk tan pnk pnk
• Primary tank fuel level signal c1
• Red
• Relay ctrl
• S100
• S103
• S106
• S146
• S213
• S231 (engine harn, approx 7-18 cm from breakout to egr valve)
• S232
• S315
• S318
• S319
• S430
• Service engine soon indicator
• Speedometer input
• Taillamp ext harn, approx 10 cm from fuel pump bal module breakout)
• Tan
• Tan a
• Throttle position sensor (on throttle body assembly)
• Trans fuse 20 10a
• Underhood fuse-relay center pnk
• Upshift lamp
• W/ calif
• W/ dual fuel tanks
• W/dual fuel tanks
• W/o dual fuel tanks

7.4L (VIN J), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams (4 of 4) for GMC Cab & Chassis C1998 2500:

• (engine harn, 7 cm from ebcm breakout)
• (engine harness, approx 13 cm into s150
• (engine harness, approx 7 cm into ebcm breakout)
• (i/p harn, 20 cm from inflatable restraint i/p module switch breakout)
• (i/p harness, approx 40 cm from i/p cluster breakout)
• (or
• (right top of cylinder head) g120
• 4wd input
• 5v ref. voltage
• A/c comp rly ctrl
• A/c request signal
• A/t
• Air conditioning system
• Aux fan relay
• Brake sw input
• Brake switch assembly (top of brake pedal)
• Brake switch input
• Check eng lp ctrl
• Clutch pedal position switch (at top of clutch pedal)
• Cooling fans system
• Cpp sw out
• Cruise control module (left rear of engine compartment, on firewall)
• Cruise ctrl sig eng
• Data link connector (under left side of dash)
• Distributor
• Ebcm breakout)
• Ecm-b f11
• Egr cyl feed
• Egr vlv grd
• Electronic brake control module (ebcm) (left side of engine compartment)
• Est output sig
• Evo/passlock control module (center of dash)
• Force motor feed
• Force motor return
• Four whl dr sig
• Four whl dr sig lo
• Fuel a pump prime connector
• Fuel lvl input
• Fuel pump relay
• Fuel pump rly ctrl
• Fuse 20a g12
• G120 (right top of cylinder head)
• Ground
• High voltage coil wire
• Hot at all times
• Hot in run
• I/p fuse block
• Ign coil out
• Ign input
• Ign timing sig.
• Ignition
• Ignition coil (top left rear of engine)
• Ignition coil driver (top left rear of engine)
• Ignition feed
• Inlet air actuator
• M/t
• M4 brake fuse 18 10a n3
• Pnk
• Pnk a
• Pressure switch input
• Radio
• Red
• S101
• S103
• S111 (engine harness, approx 7 cm from ebcm breakout)
• S151
• S152
• S153
• S221
• S222
• Sensor ground
• Sensor return
• Serial data sig
• Shift ind lp out
• Speed sensor
• Speed sensor input
• Stoplamp/ clutch switch input
• Switch signal
• Trans input speed rtn
• Trans input speed sig
• Transfer case control module (under dash, on steering column support bracket)
• Transfer case switch (left top of transfer case)
• Transmissions system (four wheel drive indicator circuit
• Underhood fuse- relay center
• Vcm sig
• Vehicle control module (vcm) (left side of engine compt)
• Vss input
• Vss sig out

EXTERIOR LIGHTS

Backup Lamps Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Backup Lamps Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (left side of transmission) backup lamp switch
• A/t
• Backup lamps signal (trailer tow package) (wire cut and taped to harness)
• G415 (left frame rail, behind bumper)
• Hot in run or start
• I/p fuse block
• Left backup lamp
• M/t
• Mirrors system
• Park/neutral position switch (left center of transmission)
• Pnk
• Right backup lamp
• S411
• S414
• Turn b/u fuse 16 20a

Exterior Lamps Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Exterior Lamps Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (dash harness, 12 cm from steering column breakout) s210
• (dash harness, 4cm into instrument cluster breakout) s267
• (dash harness, 8cm into instrument cluster breakout) s214
• (forward lamps harn, 7cm from left headlamp breakout) s122
• (forward lamps harness, 5cm from right headlamp breakout) s127
• (front to rear body harness, near chmsl harness breakout)
• (license lamp harness, 15cm from left license lamp toward taillamp breakout) s415
• (rear lamps harn, 28cm from trailer harness breakout) (w/ trailer pkg) s413
• (rear lamps harness, near taillamps extension harness break- out) s412
• Auxiliary lead (taped to harness)
• Backup lights circuit
• Cab clearance lamps
• Cargo lamp
• Cargo lamp switch
• Center high mount stop lamp
• Chmsl lp
• Column harness breakout)
• Cr lp
• Cruise control system
• Ctsy fuse 20a
• Fuse block
• G108 (left radiator support, near left headlamp)
• G119 (right front of engine block)
• G1o1 (right inner fender, below underhood reel lamp)
• G201 (right side of dash)
• G202 (behind left side of dash)
• G305 (right "b" pillar)
• G415 (left frame rail, behind bumper)
• H9 turn pwr h8 haz pwr h7 flshr out g8 gnd
• Hazard
• Headlamp & panel dimmer switch
• Headlights system
• Hot at all times
• Hot in run, bulb test or start
• I/p fuse block
• Instru- ment cluster
• Interior lights system
• Left
• Left front marker lamp
• Left front park/ turn lamps
• Left tail/ stop/ turn lamp
• Left turn indic
• License lamp
• License lamps
• Maxi fuse 30a
• Nca
• Normal
• Off
• Park
• Park lps fuse 9 20a
• Pickup
• Pnk
• Rear clearance lamps circuit
• Red
• Rheo- stat
• Right
• Right front marker lamp
• Right front park/ turn lamps
• Right tail/ stop/ turn lamp
• Right turn indic
• S107
• S119 (forward lamps harn, 20cm from washer pump breakout)
• S123
• S128
• S204
• S215
• S242
• S259
• S299
• S316
• S411
• S416
• S419
• S421 (rear lamp harness, 7cm from license lamp breakout)
• S422 (rear lamp harn, 7cm from trailer harness breakout)
• S424
• Stop- lamp relay (except subur- ban/ utility)
• Stop/ haz fuse 1 20a
• Suburban/ utility
• Tcc/ stop lamp switch (top of brake pedal)
• Trailer towing adapter (wires are cut and taped to harness)
• Turn- b/u fuse 16 15a
• Turn/ hazard switch
• Turn/hazard flasher (convenience center: under left side of dash)
• Under- hood fuse relay center (left rear of engine compt.)
• Under- hood fuse- relay center (left rear of engine compt.)
• W/ dual rear wheels
• W/ step bumper
• W/o step bumper

GROUND DISTRIBUTION

Ground Distribution Wiring Diagram (1 of 4) for GMC Cab & Chassis C1998 2500

List of elements for Ground Distribution Wiring Diagram (1 of 4) for GMC Cab & Chassis C1998 2500:

• (i/p harness, approx 24 cm from instrument cluster breakout)
• (left front of intake manifold)
• (right front of engine)
• A16
• Ashtray lamp
• Audio alarm module
• Automatic transfer case control module
• Automatic transfer case select switch
• Auxiliary cooling fan motor
• Auxiliary heater control switch (suburban/ utility)
• Auxiliary power outlet
• Btsi ground
• C10
• Cargo lamp switch (pickup)
• Cigar lighter
• Convenience center
• D10
• D12
• D13
• Data link connector
• Daytime running lamps module
• Fog lamp switch
• Front windshield wiper/ washer pump motor
• G101 (right front wheelhouse)
• G101 (right inner fender, below underhood reel lamp)
• G105 (right rear of engine compt)
• G108 (left radiator support, near left headlamp)
• G110 (diesel)
• G117 (right rear of engine)
• G119 (gasoline)
• G202 (behind left side of dash)
• Headlamp and panel dimmer switch
• Heater and a/c control switch
• Hvac control module
• I/p compartment lamp
• Ignition switch ground
• Inflatable restraint i/p module enable switch
• Left battery
• Left fog lamp
• Left front door jamb switch
• Left front park/ turn lamp
• Left high beam headlamp
• Left high/ low beam headlamp
• Left horn
• Left low beam headlamp
• Low coolant level indicator module
• Radio
• Rear liftgate release switch (suburban/ utility)
• Rear window washer pump motor
• Rear window wiper/ washer switch
• Rear window wiper/ washer switch (suburban/ utility)
• Right fog lamp
• Right front door jamb switch
• Right front park/ turn lamp
• Right high beam headlamp
• Right high/ low beam headlamp
• Right horn
• Right low beam headlamp
• S123 (forward lamps harness, approx 20 cm from left park/lamp breakout)
• S128 (forward lamps harness, approx 5 cm from right headlamp breakout)
• S158 (in washer pump jumper harness)
• S204 (i/p harness, approx 8 cm from dlc harness breakout)
• S218 (i/p harness, aprrox 16 cm from radio harness breakout)
• S298
• Spare
• Spot lamp
• Spot lamp relay
• Steering column ground
• To s316 (diagram 3 of 4)
• Transfer case control module
• Transfer case select switch
• Turn/ hazard flasher
• Uncoated
• W/ dual horns
• W/ quad headlamps
• Windshield wiper motor module

Ground Distribution Wiring Diagram (2 of 4) for GMC Cab & Chassis C1998 2500

List of elements for Ground Distribution Wiring Diagram (2 of 4) for GMC Cab & Chassis C1998 2500:

• (4wd harness, approx 10 cm from transfer case relay breakout)
• (engine harness, 8-16 cm from a/c compressor clutch connector)
• (engine harness, approx 16 cm into vehicle speed sensor breakout)
• (i/p harness, approx 8 cm from i/p cluster breakout)
• (oxygen sensor jumper harness, approx 22 cm into harness)
• (right front of engine block) g119
• 87a
• A/c compressor clutch
• A/c compressor clutch relay
• A/c compressor cycling switch
• A/c compressor pressure switch
• A/c low pressure switch
• Air injection reactor pump (7.4l only)
• Automatic transfer case module
• Blower motor
• Brake pressure warning switch
• Cruise control module
• Data link connector
• Diesel
• E16
• Electronic brake control module
• Evo passlock module
• Except suburban/ utility
• Front axle actuator
• Fuel heater
• Fuel pump and sender
• Fuel pump balance module
• Fuel pump relay
• G131 (near thermostat housing)
• G134 (front top of engine)
• Gasoline
• Glow plug relay
• Heated oxygen sensor bank 1 sensor 1
• Heated oxygen sensor bank 1 sensor 2
• Heated oxygen sensor bank 1 sensor 3
• Heated oxygen sensor bank 2 sensor 2
• Ignition coil module
• Instrument cluster
• Low coolant level sensor
• Mass airflow sensor
• Park/ neutral position switch
• S103 (vin j-engine harness, approx 12 cm from fuel injector breakout, except vin j-engine harness, approx 11 cm from breakout to egr valve)
• S107 (vin j-engine harness, approx 18 cm from fuse-relay center breakout, except vin j-engine harness, 25-35 cm from breakout to egr valve)
• S147 (vin j-engine harness, approx 5 cm from fuel injector breakout, except vin j-engine harness, approx 6 cm from egr breakout)
• S149
• S156
• S162 (except vin j-engine harness, approx 17 cm from starter solenoid breakout, vin j-engine harness, approx 41 cm from left oxygen sensor breakout)
• S185
• S186
• S215
• S302
• S317 (taillamp extension harness, approx 10 cm from fuel pump and sender breakout)
• Secondary fuel gage sender
• Starter relay
• Stoplamp relay
• Trans range switch
• Transfer case relay
• Under- hood lamp
• Under- hood reel lamp
• Underhood fuse- relay center
• Underhood reel lamp
• Vehicle control module
• Vehicle speed sensor
• W/ dual tanks
• W/o dual tanks
• Water in fuel sensor
• Water valve (suburban/ utility)

Ground Distribution Wiring Diagram (3 of 4) for GMC Cab & Chassis C1998 2500

List of elements for Ground Distribution Wiring Diagram (3 of 4) for GMC Cab & Chassis C1998 2500:

• (crossbody harness, approx 12cm right of left door harness breakout)
• (hvac harn, approx 8cm from recirculation door breakout s244
• (i/p harness, approx 8 cm from i/p cluster breakout)
• (inside left front door harness, near tweeter)
• (power lumbar seat jumper, approx 20 cm from right power seat breakout)
• A/t only
• Automatic transfer case control module
• Bench seat
• Blower motor relay (high)
• Cargo lamp
• Center high mount stop- lamp
• Data link connector
• Diesel
• Door lock relay
• Electrochromic rearview mirror w/ compass
• Evo passlock module
• Four-wheel drive indicator lamp
• From s204 (diagram 1 of 4)
• Front blower motor
• Fuel gage sender
• Fuel pump and sender
• Fuel pump balance module
• Fuel pump relay
• G134 (front top of engine)
• G201 (right side of dash)
• G416 (inside left framerail, near rear crossmember)
• Instrument cluster
• Interior lamp control module
• Left clearance lamp
• Left front power window switch
• Left front seat belt switch
• Left illuminated vanity mirror
• Left power lumbar support motor
• Left power seat switch seat
• Left rear power window switch
• Mass airflow sensor
• Mode door motor
• Others
• Power amplifier
• Power amplifier relay
• Power lumbar motor
• Power outside rearview mirror switch
• Power seat adjuster switch
• Powertrain control module
• Rear window lockout switch
• Recirculation door motor
• Remote control door lock receiver
• Right clearance lamp
• Right front power seat lumbar motor
• Right front power window switch
• Right front seat belt switch
• Right illuminated vanity mirror
• Right rear power window switch
• Roof marker lamps
• S103 (engine harness, approx 11 cm from breakout to right side glow plugs)
• S215
• S251
• S259 (crossbody harness, approx 6 cm into seat belt switch breakout)
• S303
• S316 (vanity mirror jumper harness, approx 10 cm toward left illuminated vanity mirror)
• S317 (taillamp extension harness, approx 10 cm from fuel gage sender breakout)
• S319 (taillamp extension harn, approx 7cm from fuel pump and sender breakout)
• S500
• Secondary fuel gage sender
• Temperature door motor
• Transfer case mode selector illumination lamp
• Under- hood fuse- relay center
• Vehicle speed sensor buffer
• W/ dual tanks

Ground Distribution Wiring Diagram (4 of 4) for GMC Cab & Chassis C1998 2500

List of elements for Ground Distribution Wiring Diagram (4 of 4) for GMC Cab & Chassis C1998 2500:

• (license lamps harness, approx 4 cm from tail- lamp harness breakout)
• (rear heat and a/c harness, 7 cm from blower motor resistor breakout)
• (rear lamps harness, 17-33 cm from taillamps extension breakout)
• Air pump (5.7l)
• Auxiliary blower motor
• Auxiliary heater- a/c logic module
• Auxiliary mode door motor
• Auxiliary temp door motor
• Center high mount stoplamp
• Diesel chassis cab & heavy duty
• Diesel except chassis cab & heavy duty
• Door contact button
• Door lock control module (w/ cargo doors)
• Endgate marker lamps
• Front auxiliary heater-a/c control module
• Front dome lamp
• G110 (left front of engine)
• G202 (left side of dash)
• G305 (right 'b' pillar)
• G415 (frame ground, rear of vehicle)
• G415 (left frame rail, behind bumper)
• Inflatable restraint front end sensor
• Inflatable restraint sensing and diagnostic module
• Left cargo door defogger grid
• Left front clearance lamp
• Left license lamp
• Left rear clearance lamp
• Left rear fender
• Left rear tail, stop, license, turn & backup lamps
• Left rear tail, stop, turn & backup lamps
• Left tail, stop, turn & backup lamps
• Overhead console lamps
• Pickup w/ dual rear wheels
• Rear auxiliary heater-a/c control module
• Rear dome lamp
• Rear door jamb switch
• Rear liftgate window defogger grid
• Rear wiper motor module
• Right cargo door defogger grid
• Right front clearance lamp
• Right license lamp
• Right rear clearance lamp
• Right rear fender
• Right rear tail, stop, license, turn & backup lamps
• Right rear tail, stop, turn & backup lamps
• Right tail, stop, turn & backup lamps
• S167 (engine harn, near g110)
• S307 (rear hvac control harness, approx 10 cm from hvac logic module breakout)
• S403
• S410 (utility-front to rear lamps harness, 12-22 cm from right rear door speaker breakout, suburban-front to rear body harness, 12-22 cm from right rear door speaker breakout)
• S411
• S411 (rear lamps harness, 17-33 cm from taillamps extension breakout)
• S416
• Suburban & utility
• Trailer ground (taped back)
• Utility only

HEADLIGHTS

Headlight Wiring Diagram, with Quad Headlamps for GMC Cab & Chassis C1998 2500

List of elements for Headlight Wiring Diagram, with Quad Headlamps for GMC Cab & Chassis C1998 2500:

• (forward lamps harn, approx 12cm from left headlamp breakout toward windshield washer pump)
• (i/p harn, near strng col harn breakout; except 1998 gas) (i/p harn, near auxiliary power outlet; 1998 gas)
• Acc
• Brake ind ctrl
• Brake warn in
• Bulb test
• Convenience center (under left side of dash)
• Daytime running lamps module (behind left side of dash)
• Daytime running lamps relay
• Diode 203 (i/p harness, right side of steering column)
• Drl indicator
• Drl relay ctrl
• Drl-fog fuse 15 20a
• Exterior lights system
• Fog lamp relay
• Fog lamp switch
• G101 (right inner fender)
• G101 (right inner fender, below underhood reel lamp)
• G108 (left radiator support)
• G134 (front top of engine)
• G202 (behind left side of dash)
• Gages fuse 4 10a
• Ground
• Head
• Head- lamp dimmer switch
• Headlamp and panel dimmer switch
• High beam indicator
• Hot at all times
• Hot in run, bulb test or start
• I/p fuse block (left side of dash)
• Ignition
• Ignition switch
• Illum lamp
• Ind bulb chk
• Instrument cluster
• Instrument cluster system (brake warning indicator)
• Interior lights system
• Lamp feed
• Left fog lamp
• Left high beam head- lamp
• Left low beam head- lamp
• Lighting fuse 8 50a
• Lock
• Nca
• Off
• On indicator
• Park
• Park brake sig
• Park brake warning switch
• Pk lps fuse 9 20a
• Pnk
• Red
• Red c
• Right fog lamp
• Right high beam head- lamp
• Right low beam head- lamp
• Run
• S120 (forward lamps harn, near windshield washer pump breakout toward left hdlp)
• S121
• S123
• S125 (i/p harn, approx 13cm from left rear engine compt grommet towards forward lamps harn; except 1998 diesel) (i/p harn, approx 20cm from cluster breakout; 1998 diesel)
• S128
• S204
• S205
• S210
• S213
• S215
• S298
• Start
• Tan
• Underhood fuse/relay center (left rear of engine compt)
• W/ fog lamps

Headlight Wiring Diagram, with Sealed Beam Headlamps for GMC Cab & Chassis C1998 2500

List of elements for Headlight Wiring Diagram, with Sealed Beam Headlamps for GMC Cab & Chassis C1998 2500:

• (forward lamps harn, approx 12cm from left headlamp breakout toward windshield washer pump)
• (high)
• (i/p harn, near strng col harn breakout; except 1998 gas) (i/p harn, near auxiliary power outlet; 1998 gas)
• (low)
• Acc
• Brake ind ctrl
• Brake warn in
• Bulb test
• Convenience center (under left side of dash)
• Daytime running lamps module (behind left side of dash)
• Daytime running lamps relay
• Diode 203 (i/p harness, right side of steering column)
• Drl indicator
• Drl relay ctrl
• Drl-fog fuse 15 20a
• Exterior lights system
• Fog lamp relay
• Fog lamp switch
• G101 (right inner fender)
• G101 (right inner fender, below underhood reel lamp)
• G108 (left radiator support)
• G134 (front top of engine)
• G202 (behind left side of dash)
• Gages fuse 4 10a
• Ground
• Head
• Head- lamp dimmer switch
• Headlamp and panel dimmer switch
• High beam indicator
• Hot at all times
• Hot in run, bulb test or start
• I/p fuse block (left side of dash)
• Ignition
• Ignition switch
• Illum lamp
• Ind bulb chk
• Instrument cluster
• Instrument cluster system (brake warning indicator)
• Interior lights system
• Lamp feed
• Left fog lamp
• Left head- lamp
• Lighting fuse 8 50a
• Lock
• Nca
• Off
• On indicator
• Park
• Park brake sig
• Park brake warning switch
• Pk lps fuse 9 20a
• Pnk
• Red
• Red c
• Right fog lamp
• Right head- lamp
• Run
• S120 (forward lamps harn, near windshield washer pump breakout toward left headlamp)
• S121
• S123
• S125 (i/p harn, approx 13cm from left rear engine compt grommet towards forward lamps harn; except 1998 diesel) (i/p harn, approx 20cm from cluster breakout; 1998 diesel)
• S128
• S204
• S205
• S210
• S213
• S215
• S298
• Start
• Tan
• Tan c
• Underhood fuse/relay center (left rear of engine compt)
• W/ fog lamps

HORN

Horn Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Horn Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (forward lamps harn, 26.5 cm from left headlamp breakout) s124
• Base
• C100
• C102
• C242
• C244
• C266
• Convenience center
• G101 (right inner fender, below underhood reel lamp)
• Horn fuse 20a
• Horn relay
• Horn slip ring
• Horn switch
• Hot at all times
• Jumper wire
• Left horn (front of vehicle)
• Nca
• Police package
• Remote control door lock receiver
• Right horn (front of vehicle) (w/front end appearance package only)
• S128
• Steering wheel
• Underhood fuse/relay center

INSTRUMENT CLUSTER

5.0L

5.0L (VIN M), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (6 bulbs)
• (taillamp extension harn, near fuel pump harness breakout)
• 5v ref
• A/t
• A/t 4wd
• Accy
• Air bag ind
• Anti- lock brakes ind
• Anti-lock brakes system
• Bat ind
• Brake ind
• Brake pressure warning switch (on rear of ebcm casting)
• Brake psi
• Bulb test
• Check gauges ind
• Check gauges lamp driver
• Daytime running lamps ind
• Daytime running lamps module (behind left side of dash, taped to dash harness)
• Electronic brake control module (on left side of engine compt)
• Engine controls system (fuel pump balance relay)
• Engine coolant temperature sender (left cylinder head)
• Exterior lights system
• Fuel
• Fuel gauge
• Fuel in
• Fuel pump & sender (in front fuel tank)
• Fuel pump & sender (in fuel tank)
• Fuel pump balance module (inside left side frame rail)
• Fuel pump/ oil pressure switch & sender (rear top center of engine)
• Fuel tank
• G119 (right front of engine block)
• G131 (near thermo- stat housing)
• G134 (front top of engine)
• Gauges fuse 4 10a
• Headlights system
• Hi beam ind
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block (left end of dash)
• Ign
• Ign e mini fuse 10a
• Ign sw
• Ignition coil (right rear of engine)
• Ignition switch
• Illum
• Illumination
• Instrument cluster
• Interior lights system
• Led dimming
• Left turn ind
• Lock
• M/t
• M/t 4wd & all 2wd
• Mil ind
• Off
• Oil gauge
• Parity prndl
• Park brake warning switch (on park brake pedal bracket)
• Pk brake
• Pnk
• Prndl
• Prndl a
• Prndl b
• Prndl c
• Right turn ind
• Run
• S103
• S146
• S147
• S162
• S213
• S215
• S317
• S430
• Safety belt ind
• Secondary fuel gage sender (in rear fuel tank)
• Sens rtrn
• Service engine soon ind
• Single dual fuel tanks
• Speedo
• Speedometer
• Start
• Starting/charging system
• Tach
• Tan
• Temp gauge
• Trans fuse 20 10a
• Transmission range selector (left side of transmission)
• Twisted pair
• Underhood fuse- relay center
• Upshift ind
• Upshift ind (m/t only)
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left rear of transmission or transfer case)
• Vehicle speed sensor (vss) adapter
• Voltmeter
• Vss
• Warning systems

5.7L

5.7L (VIN R), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (6 bulbs)
• (taillamp extension harn, near fuel pump harness breakout)
• 5v ref
• A/t
• A/t 4wd
• Accy
• Air bag ind
• Anti- lock brakes ind
• Anti-lock brakes system
• Bat ind
• Brake ind
• Brake pressure warning switch (on rear of ebcm casting)
• Brake psi
• Bulb test
• Check gauges ind
• Check gauges lamp driver
• Daytime running lamps ind
• Daytime running lamps module (behind left side of dash, taped to dash harness)
• Electronic brake control module (on left side of engine compt)
• Engine controls system (fuel pump balance relay)
• Engine coolant temperature sender (left cylinder head)
• Exterior lights system
• Fuel
• Fuel gauge
• Fuel in
• Fuel pump & sender (in front fuel tank)
• Fuel pump & sender (in fuel tank)
• Fuel pump balance module (inside left side frame rail)
• Fuel pump/ oil pressure switch & sender (rear top center of engine)
• Fuel tank
• G119 (right front of engine block)
• G131 (near thermo- stat housing)
• G134 (front top of engine)
• Gauges fuse 4 10a
• Headlights system
• Hi beam ind
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block (left end of dash)
• Ign
• Ign e mini fuse 10a
• Ign sw
• Ignition coil (right rear of engine)
• Ignition switch
• Illum
• Illumination
• Instrument cluster
• Interior lights system
• Led dimming
• Left turn ind
• Lock
• M/t
• M/t 4wd & all 2wd
• Mil ind
• Off
• Oil gauge
• Parity prndl
• Park brake warning switch (on park brake pedal bracket)
• Pk brake
• Pnk
• Prndl
• Prndl a
• Prndl b
• Prndl c
• Right turn ind
• Run
• S103
• S146
• S147
• S162
• S213
• S215
• S317
• S430
• Safety belt ind
• Secondary fuel gage sender (in rear fuel tank)
• Sens rtrn
• Service engine soon ind
• Single dual fuel tanks
• Speedo
• Speedometer
• Start
• Starting/charging system
• Tach
• Tan
• Temp gauge
• Trans fuse 20 10a
• Transmission range selector (left side of transmission)
• Twisted pair
• Underhood fuse- relay center
• Upshift ind
• Upshift ind (m/t only)
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left rear of transmission or transfer case)
• Vehicle speed sensor (vss) adapter
• Voltmeter
• Vss
• Warning systems

6.5L

6.5L (VIN F), Instrument Cluster Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Instrument Cluster Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500:

• (6 bulbs)
• Air bag ind
• Anti- lock brakes ind
• Anti-lock brakes system
• Bat ind
• Brake ind
• Check gauges ind
• Check gauges lamp driver
• Daytime running lamps ind
• Engine controls system
• Engine coolant temperature sensor (on top right front of engine, near thermostat housing)
• Exterior lights system
• Fuel gauge
• G117 (top rear of right cylinder head)
• G119 (right front of engine block)
• G134 (front top of engine)
• G202 (behind left side of dash)
• Generator
• Gnd
• Headlights system
• Hi beam ind
• Ign
• Illum
• Illumination
• Instrument cluster
• Interior lights system
• Led dimming
• Left turn ind
• Low coolant ind
• Low coolant level indicator module (behind center of dash)
• Low coolant level sensor (in coolant reservoir, right side of engine compt)
• Oil press
• Oil pressure switch & sender (under intake manifold, center of engine)
• Parity prndl
• Pnk
• Prndl
• Prndl a
• Prndl b
• Prndl c
• Right turn ind
• S107
• S147
• S215
• S298
• Safety belt ind
• Service engine soon ind
• Service throttle soon ind
• Solid state
• Speed- ometer
• Starting/charging system
• Tach
• Tan
• Temp gauge
• Transmission range selector (left side of transmission)
• Up- shift ind (m/t)
• Volt- meter
• Wait to start ind
• Warning system
• Water in fuel ind
• Water-in fuel sensor (top rear of engine)

6.5L (VIN F), Instrument Cluster Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Instrument Cluster Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500:

• (engine harn, s157
• (i/p harn, 18 cm into cluster breakout)
• (i/p harn, 5 cm into power steering control module breakout)
• 20 cm into ebcm breakout)
• 4wd a/t
• 4wd m/t & all 2wd
• A/t
• Accy
• Anti-lock brakes system
• Brake ind
• Brake ind in
• Brake pressure warning switch (on rear of ebcm casting)
• Brake psi
• Bulb test
• C100
• Daytime running lamps module (behind left side of dash, taped to panel wiring harness)
• Diode 1
• Dual fuel tanks
• Electronic brake control module (left side of engine compt)
• Eng 1 mini fuse 20a
• Engine controls system
• Engine controls system (fuel pump balance relay)
• Fuel gage sender (in front fuel tank)
• Fuel pump & sender
• Fuel pump balance module (inside left side of frame rail)
• G119 (right front of engine block)
• G134 (front top of engine)
• Gauges fuse 4 10a
• Hot in run, bulb test or start
• I/p fuse block (left end of dash)
• Ign e mini fuse 10a
• Ign sw
• Ignition switch
• Lock
• M/t
• Off
• Park brake warning switch (on parking brake pedal bracket)
• Pk brake
• Pnk
• Radio
• Run
• S103
• S108
• S147
• S211
• S213
• S215
• S221
• S315
• S317
• Secondary fuel gage sender (in rear fuel tank)
• Single fuel tank
• Start
• Trans fuse 20 10a
• Transmission system
• Twisted pair
• Underhood fuse-relay center (left rear of engine compt)
• Vehicle speed sensor (left rear of transmission or transfer case)
• Vehicle speed sensor (vss) adapter
• Vehicle speed sensor buffer (behind right side of dash)

6.5L (VIN S), Instrument Cluster Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Instrument Cluster Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500:

• (6 bulbs)
• Air bag ind
• Anti- lock brakes ind
• Anti-lock brakes system
• Bat ind
• Brake ind
• Check gauges ind
• Check gauges lamp driver
• Daytime running lamps ind
• Engine controls system
• Engine coolant temperature sensor (on top right front of engine, near thermostat housing)
• Exterior lights system
• Fuel gauge
• G117 (top rear of right cylinder head)
• G119 (right front of engine block)
• G134 (front top of engine)
• G202 (behind left side of dash)
• Generator
• Gnd
• Headlights system
• Hi beam ind
• Ign
• Illum
• Illumination
• Instrument cluster
• Interior lights system
• Led dimming
• Left turn ind
• Low coolant ind
• Low coolant level indicator module (behind center of dash)
• Low coolant level sensor (in coolant reservoir, right side of engine compt)
• Oil press
• Oil pressure switch & sender (under intake manifold, center of engine)
• Parity prndl
• Pnk
• Prndl
• Prndl a
• Prndl b
• Prndl c
• Right turn ind
• S107
• S147
• S215
• S298
• Safety belt ind
• Service engine soon ind
• Service throttle soon ind
• Solid state
• Speed- ometer
• Starting/charging system
• Tach
• Tan
• Temp gauge
• Transmission range selector (left side of transmission)
• Up- shift ind (m/t)
• Volt- meter
• Wait to start ind
• Warning system
• Water in fuel ind
• Water-in fuel sensor (top rear of engine)

6.5L (VIN S), Instrument Cluster Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Instrument Cluster Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500:

• (engine harn, s157
• (i/p harn, 18 cm into cluster breakout)
• (i/p harn, 5 cm into power steering control module breakout)
• 20 cm into ebcm breakout)
• 4wd a/t
• 4wd m/t & all 2wd
• A/t
• Accy
• Anti-lock brakes system
• Brake ind
• Brake ind in
• Brake pressure warning switch (on rear of ebcm casting)
• Brake psi
• Bulb test
• C100
• Daytime running lamps module (behind left side of dash, taped to panel wiring harness)
• Diode 1
• Dual fuel tanks
• Electronic brake control module (left side of engine compt)
• Eng 1 mini fuse 20a
• Engine controls system
• Engine controls system (fuel pump balance relay)
• Fuel gage sender (in front fuel tank)
• Fuel pump & sender
• Fuel pump balance module (inside left side of frame rail)
• G119 (right front of engine block)
• G134 (front top of engine)
• Gauges fuse 4 10a
• Hot in run, bulb test or start
• I/p fuse block (left end of dash)
• Ign e mini fuse 10a
• Ign sw
• Ignition switch
• Lock
• M/t
• Off
• Park brake warning switch (on parking brake pedal bracket)
• Pk brake
• Pnk
• Radio
• Run
• S103
• S108
• S147
• S211
• S213
• S215
• S221
• S315
• S317
• Secondary fuel gage sender (in rear fuel tank)
• Single fuel tank
• Start
• Trans fuse 20 10a
• Transmission system
• Twisted pair
• Underhood fuse-relay center (left rear of engine compt)
• Vehicle speed sensor (left rear of transmission or transfer case)
• Vehicle speed sensor (vss) adapter
• Vehicle speed sensor buffer (behind right side of dash)

7.4L

7.4L (VIN J), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Instrument Cluster Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (6 bulbs)
• (taillamp extension harn, near fuel pump harness breakout)
• 5v ref
• A/t
• A/t 4wd
• Accy
• Air bag ind
• Anti- lock brakes ind
• Anti-lock brakes system
• Bat ind
• Brake ind
• Brake pressure warning switch (on rear of ebcm casting)
• Brake psi
• Bulb test
• Check gauges ind
• Check gauges lamp driver
• Daytime running lamps ind
• Daytime running lamps module (behind left side of dash, taped to dash harness)
• Electronic brake control module (on left side of engine compt)
• Engine controls system (fuel pump balance relay)
• Engine coolant temperature sender (left cylinder head)
• Exterior lights system
• Fuel
• Fuel gauge
• Fuel in
• Fuel pump & sender (in front fuel tank)
• Fuel pump & sender (in fuel tank)
• Fuel pump balance module (inside left side frame rail)
• Fuel pump/ oil pressure switch & sender (rear top center of engine)
• Fuel tank
• G119 (right front of engine block)
• G131 (near thermo- stat housing)
• G134 (front top of engine)
• Gauges fuse 4 10a
• Headlights system
• Hi beam ind
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block (left end of dash)
• Ign
• Ign e mini fuse 10a
• Ign sw
• Ignition coil (right rear of engine)
• Ignition switch
• Illum
• Illumination
• Instrument cluster
• Interior lights system
• Led dimming
• Left turn ind
• Lock
• M/t
• M/t 4wd & all 2wd
• Mil ind
• Off
• Oil gauge
• Parity prndl
• Park brake warning switch (on park brake pedal bracket)
• Pk brake
• Pnk
• Prndl
• Prndl a
• Prndl b
• Prndl c
• Right turn ind
• Run
• S103
• S146
• S147
• S162
• S213
• S215
• S317
• S430
• Safety belt ind
• Secondary fuel gage sender (in rear fuel tank)
• Sens rtrn
• Service engine soon ind
• Single dual fuel tanks
• Speedo
• Speedometer
• Start
• Starting/charging system
• Tach
• Tan
• Temp gauge
• Trans fuse 20 10a
• Transmission range selector (left side of transmission)
• Twisted pair
• Underhood fuse- relay center
• Upshift ind
• Upshift ind (m/t only)
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor (left rear of transmission or transfer case)
• Vehicle speed sensor (vss) adapter
• Voltmeter
• Vss
• Warning systems

INTERIOR LIGHTS

Courtesy Lamps Wiring Diagram, Regular Cab/Extended Cab for GMC Cab & Chassis C1998 2500

List of elements for Courtesy Lamps Wiring Diagram, Regular Cab/Extended Cab for GMC Cab & Chassis C1998 2500:

• (crossbody harn, approx 22 cm from left door harn breakout)
• (i/p harn, approx 6 cm from i/p compt box lamp breakout) s208
• (not used)
• Bat
• Cargo lamp
• Courtesy lamps
• Ctrl
• Ctsy fuse 3 20a
• Dome defeat
• Dome lamp defeat
• Door jamb
• From chmsl breakout)
• Front dome and reading lamp
• G120 (right front of engine block)
• G201 (right side of dash)
• G202 (behind left side of dash)
• Gages fuse 4 10a
• Gnd
• Headlamp and panel dimmer switch
• Horn fuse 20a
• Hot at all times
• Hot in run, bulb test or start
• I/p compartment box lamp
• I/p fuse block
• Ign sw
• Interior lamp control module (under center of dash)
• Lamp out
• Left front door jamb switch
• Left i/p courtesy lamp
• Left illuminated vanity mirror
• Mirrors system
• Nca
• Pnk
• Pnk a
• Pnk j
• Remote control door lock receiver (behind center of dash)
• Right front door jamb switch
• Right i/p courtesy lamp
• Right illuminated vanity mirror
• S113
• S162 (gas) s147 (diesel)
• S204
• S209 (i/p harn, approx 13 cm from i/p compt box lamp harn breakout)
• S213
• S218
• S242
• S244
• S246
• S248
• S251
• S312
• S316
• Underhood fuse-relay center
• Underhood lamp
• Underhood reel lamp
• W/ rke
• W/o rke

Instrument Illumination Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500

List of elements for Instrument Illumination Wiring Diagram (1 of 2) for GMC Cab & Chassis C1998 2500:

• (6) bulbs
• (at right "b" pillar)
• (behind left side of dash)
• (cross- body harn, near i/p harn breakout) s253
• (i/p harn, near i/p cluster breakout) s217
• (right side of dash)
• Audio alarm module (on convenience center)
• Automatic transfer cash select switch
• Auxiliary heater control switch (subur- ban/ utilitiy only)
• Cargo lamp switch (pickup only)
• Daytime running lamp (drl)/ radio override switch
• Daytime running lamps (drl)/ radio override switch
• Display dim sig
• Fog lamp switch
• Front auxiliary hvac control lamp
• G131 (near thermostat housing)
• G201
• G202
• G305
• Headlamp and panel dimmer switch
• Hot at all times
• Hvac control lamp
• I/p fuse block
• Illum fuse 14 10a
• Inflatable restaint i/p module enable switch
• Inflatable restaint i/p module switch
• Instrument cluster
• Liftgate release switch (subur- ban/ utilitiy only)
• Off
• Parade mode sw
• Park
• Park lps fuse 9 20a
• Pickup/ extended cab only
• Radio
• Rear auxiliary hvac control lamp
• Rear window wiper/ washer switch (subur- ban/ utilitiy only)
• Rheo- stat
• S103
• S204
• S216 (i/p harn, near i/p cluster breakout)
• S218
• S259
• S307
• Suburban & utility only
• Transfer case shift illumination lamp
• Transfer case switch
• Z56 only

Instrument Illumination Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500

List of elements for Instrument Illumination Wiring Diagram (2 of 2) for GMC Cab & Chassis C1998 2500:

• (behind left side of dash)
• (crossbody harn, approx 6 cm in left door harn breakout)
• (right side of dash)
• Ash tray lamp
• Exterior lights system
• G201
• G202
• Headlamp and panel dimmer switch
• Hot at all times
• I/p fuse block
• Left front power window switch
• Left power rearview mirror switch
• Left rear power window switch
• Off
• Parade mode sw
• Park
• Park lps fuse 9 20a
• Rear window lockout switch
• Rheo- stat
• Right front power window switch
• Right rear power window switch
• S210 (i/p harn, approx 12 cm from steering column harn breakout)
• S218
• S244
• S247
• S251
• S259
• S500
• S502 (left front door harn, near tweeter)

POWER DISTRIBUTION

Power Distribution Wiring Diagram (1 of 5) for GMC Cab & Chassis C1998 2500

List of elements for Power Distribution Wiring Diagram (1 of 5) for GMC Cab & Chassis C1998 2500:

• (auxiliary a/c harness, near blower motor relays) s401
• (diesel)
• (diesel-engine harness, 5cm from starter solenoid breakout gasoline-engine harness, near electronic brake control module breakout)
• (engine harness, approx 19cm from electronic brake control module breakout) s113
• (engine harness, near ebcm breakout)
• (gasoline)
• (i/p harness, near steering column harness breakout) s205
• (stud a)
• (stud b)
• (vanity mirror jumper harness, approx 4 cm from inside rearview mirror)
• 175a
• 7.4l
• A/c comp fuse 10a
• A/c compressor clutch relay
• Abs fuse 4 60a
• Aux fan fuse 30a
• Aux fuse 22 20a
• Auxiliary cooling fan relay
• Auxiliary high blower motor relay
• Auxiliary low blower motor relay
• Auxiliary medium blower motor relay
• Blower fuse 3 50a
• Brake lamp relay
• C13
• C205
• Camp/trail fuse 30a
• Cargo lamp switch
• Convenience center
• Ctsy fuse 3 20a
• D13
• Daytime running lamps relay
• Diode
• Drl/fog fuse 15 20a
• Dual battery
• Ecm-b fuse 20a
• Electronic brake control module
• Evo/ passlock module
• Fog lamp relay
• Front dome reading lamps
• Front dome/ reading lamps
• Fuel pump oil pressure switch and sender
• Fuel pump relay
• Fusible link (10 ga-rust)
• Gas only
• Generator (base)
• Generator (uplevel)
• Headlamp and panel dimmer switch
• Heater and a/c control switch
• High blower motor relay
• Homelink transmitter
• Horn fuse 20a
• Horn relay
• I/p compartment box lamp
• I/p fuse block
• Instrument cluster (police package)
• Interior lamp control module
• Left battery (diesel)
• Left courtesy lamp
• Left front door courtesy lamp
• Left illuminated vanity mirror
• Left rear door courtesy lamp
• Lighting fuse 8 50a
• Mega fuse block
• Nca
• Overhead console reading lamps
• Pickup only
• Pk lps fuse 9 20a
• Police package only
• Power outside rearview mirror switch
• Powertrain control module (diesel)
• Radio
• Radio batt fuse 19 10a
• Rear dome/ reading lamps
• Red
• Remote battery stud
• Right battery
• Right courtesy lamp
• Right front door courtesy lamp
• Right illuminated vanity mirror
• Right rear door courtesy lamp
• Roof clearance lamp switch
• Rr defog fuse 30a
• S101
• S110
• S242 (i/p harn, 12cm from inflatable restraint switch breakout)
• S248 (crossbody harness, approx 35 cm from rear speaker breakout)
• S278
• S312 s312
• S443
• Security/strg fuse 21 20a
• Seo fuse 30a
• Single battery (base)
• Single battery (uplevel)
• Spare power source
• Spotlamp (police package)
• Starter motor solenoid
• Stop fuse 2 30a
• Suburban/ utility
• To fusible link (diagram 4 of 5)
• To megafuse (diagram 5 of 5)
• To underhood fuse-relay center (diagram 2 of 5)
• Underhood fuse- relay center
• Underhood fuse-relay center
• Underhood lamp
• Underhood reel lamp (gas only)
• Vehicle control module (gasoline)

Power Distribution Wiring Diagram (2 of 5) for GMC Cab & Chassis C1998 2500

List of elements for Power Distribution Wiring Diagram (2 of 5) for GMC Cab & Chassis C1998 2500:

• (crew cab-crossbody harness, 1cm from door lock relay breakout except crew cab-crossbody harn, near convenience center breakout)
• (crossbody harness, 20 cm from convenience center breakout) s255
• (front-to-rear body harn, 7cm from dome lamp breakout)
• (i/p harn, 4cm from auxiliary power outlet breakout)
• (i/p harness, 12cm from steering column harness breakout) s200
• (i/p harness, 4cm from steering column harness breakout)
• (i/p harness, approx 8 cm from steering column harness breakout)
• (i/p harness, left rear of engine compartment)
• (inside left front door harness, near tweeter)
• (power lumbar seat jumper harness, approx 13 cm from right power seat breakout)
• 4cm from i/p cluster breakout) s264
• A/t
• Acc
• Audio alarm module
• Automatic
• Automatic transfer case
• Automatic transfer case control module
• Aux/pwr fuse 7 25a
• Auxiliary power connector
• C210
• Cig ltr fuse 13 20a
• Cigar lighter
• Clutch pedal position switch
• Convenience center
• Crank fuse 8 10a
• Cross body harn, 8cm from convenience center breakout)
• D14
• D15
• Data link connector
• Door lock control module (w/ cargo doors)
• Door lock relay
• E nca
• Electric
• From underhood fuse-relay center (diagram 1 of 5)
• G202 (left side of dash)
• I/p fuse block
• Ign a fuse 6 40a
• Ign b fuse 5 50a
• Ignition switch
• Instrument cluster
• Left front door lock switch
• Left front power lumbar seat switch
• Left power seat adjuster switch
• Liftgate release switch
• Lock
• M/t
• Maxi fuse 7 50a
• Nca
• Off
• Park/neutral position switch
• Pickup
• Pnk
• Power amplifier relay (suburban)
• Power seat lumbar switch
• Power wdo circuit breaker 30a
• Power window master switch
• Pwr-accy circuit breaker 20a
• Radio
• Radio fuse 17 10a
• Rear door lock switch
• Rear window lockout switch (4-dr)
• Rear window wiper/washer switch (suburban/utility)
• Red
• Remote control door lock receiver
• Right front door lock switch
• Right front power lumbar seat switch
• Right front power window switch (2 dr & utility)
• Right lumbar power seat switch
• Right power seat adjuster switch
• Rr wiper fuse 23 25a
• Run
• S201
• S218
• S236
• S237
• S256
• S266
• S270
• S299
• S300
• S434
• S501
• Start
• Starter relay
• Stop lamp switch
• Stop/haz fuse 1 20a
• Suburban only
• Suburban/ utility
• T case fuse 2 20a
• To s206 (diagram 4 of 5)
• To s207 (diagram 3 of 5)
• To s285 (diagram 5 of 5)
• To seats fuse (diagram 4 of 5)
• Trans fuse 20 10a
• Trans- mission controls
• Transfer case control module
• Turn/ hazard switch
• Underhood fuse-relay center
• W/bench seat
• Windshield wiper motor module
• Windshield wiper/ washer switch
• Wiper fuse 11 25a

Power Distribution Wiring Diagram (3 of 5) for GMC Cab & Chassis C1998 2500

List of elements for Power Distribution Wiring Diagram (3 of 5) for GMC Cab & Chassis C1998 2500:

• (a/t)
• (engine harness, 10cm from fuel injector breakout) pnk s104
• (engine harness, 12cm from fuel injector breakout)
• (engine harness, 20cm from ebcm breakout)
• (engine harness, 30cm from ebcm breakout)
• (engine harness, approx 13 cm from ignition coil breakout)
• (engine harness, approx 30 cm from egr harness breakout)
• (engine harness, approx 5 cm from backup lamp switch harness breakout)
• (i/p harness, 12cm from steering column harness breakout) pnk
• (i/p harness, 4cm from steering column harness breakout)
• (in injector harness jumper)
• (m/t)
• (oxygen sensor jumper harness, approx 19cm into harness)
• (taillamp extension harness, approx 17 cm from fuel pump balance module breakout)
• 4.3l
• 5.0l, 5.7l
• 6.5l
• 7.4l
• 7.4l w/ california emissions
• A/c clutch relay
• A/c compressor clutch relay
• Air bag fuse 10 10a
• Air intake recirculation relay (5.7l)
• Air relay
• Audio alarm module
• B pnk
• Backup lamp switch
• C pnk
• C11
• C12
• Camshaft position sensor
• Convenience center
• Crank- shaft position sensor
• Daytime running lamps module
• Daytime running lamps relay
• Diesel
• Ecm 1 mini fuse 20a
• Egr boost solenoid
• Egr linear pwm valve solenoid
• Egr solenoid
• Electrochromatic rearview mirror w/ compass
• Eng-1 mini fuse 20a
• Engine shutoff solenoid
• Evaporative emission canister vent
• Evaporative emissions canister purge solenoid valve
• Evo/ passlock module
• From ignition switch (diagram 2 of 5)
• Fuel heater
• Fuel injector
• Fuel pump balance module
• Fuel pump balance relay
• Fuel solenoid driver
• Fuel tank sender module (4.3l)
• Gasoline
• Gauges fuse 4 10a
• Glow plug relay
• Headlamp/ panel dimmer switch
• Heated oxygen sensor bank 1 sensor 1
• Heated oxygen sensor bank 1 sensor 2
• Heated oxygen sensor bank 1 sensor 3
• Heated oxygen sensor bank 2 sensor 1
• I/p fuse block
• Ign e mini fuse 10a
• Ignition coil
• Ignition control module
• Inflatable restraint i/p module switch
• Inflatable restraint sensing and diagnostic module
• Instrument cluster
• Interior lamp control module or remote control door lock receiver
• Low coolant level indicator module (diesel)
• M/t
• Mass air flow sensor
• Mass airflow sensor
• Others
• Park/ neutral position switch
• Pnk
• Pnk s104
• Pnk s154
• Pnk s207
• Powertrain control module
• S104
• S108
• S146
• S148
• S155 pnk
• S161
• S161 (engine harness, approx 7cm from egr breakout) pnk
• S166
• S190
• S213 pnk
• S315
• Transfer case control module (selectable 4wd electric shift)
• Transfer case select switch
• Turn b/u fuse 16 20a
• Turn signal switch
• Underhood fuse-relay center
• Vehicle control module
• Vehicle speed sensor buffer (diesel)
• Water-in- fuel sensor

Power Distribution Wiring Diagram (4 of 5) for GMC Cab & Chassis C1998 2500

List of elements for Power Distribution Wiring Diagram (4 of 5) for GMC Cab & Chassis C1998 2500:

• (auxiliary a/c harness, 17cm from blower motor relays)
• (engine harness, 7cm from ebcm) breakout)
• (hvac harness, approx 4 cm from recirculation door breakout)
• (i/p harness, 6cm from steering column harness breakout)
• (i/p harness, approx 4 cm from steering column breakout)
• (i/p harness, approx 7cm from inflatable restraint switch breakout) s268
• (rear hvac control harn, approx 5 cm from hvac logic module breakout) s308
• 4wd fuse 24 25a
• A13
• Automatic transfer case control module
• Automatic transfer case select switch
• Auxiliary battery
• Auxiliary battery relay (left rear of engine compt)
• Auxiliary heater and a/c control logic module
• Auxiliary heater and a/c control module (front)
• Auxiliary heater and a/c control module (rear)
• Auxiliary high blower motor relay
• Auxiliary low blower motor relay
• Auxiliary medium blower motor relay
• Auxiliary mode door motor
• Auxiliary temperature door motor
• Brake fuse 18 10a
• C205
• Convenience center
• Cruise control module (gas only)
• Cruise control switch
• Cruise fuse 6 10a
• Diesel
• E10
• Electronic brake control module
• Except diesel
• From ignition switch (diagram 2 of 4)
• From underhood e fuse-relay center (diagram 2 of 5)
• From underhood fuse-relay center (diagram 1 of 5)
• Front axle actuator
• Front heated seats fuse 40a
• Fusible link
• G100 (left front fender)
• Heated mirror relay
• Heater and a/c control switch
• Htr-a/c fuse 12 25a
• Hvac control module
• I/p fuse block
• Left heated seat module
• Left heated seat switch
• Mirrors fuse 10a
• Mode door motor
• Recirculation door motor
• Right heated seat module
• Right heated seat switch
• Rr hvac fuse 5 10a
• S151
• S192
• S206
• S233
• S234
• S235
• S238
• S243
• S400
• Seats fuse 40a
• Spare power source
• Stop lamp switch
• Temperature door motor
• Transfer case select switch
• Underhood fuse-relay center
• Vehicle control module (gass only)
• W/ cargo doors
• W/ lift- gate
• W/ rear defrost

Power Distribution Wiring Diagram (5 of 5) for GMC Cab & Chassis C1998 2500

List of elements for Power Distribution Wiring Diagram (5 of 5) for GMC Cab & Chassis C1998 2500:

• (battery harn, left side of engine compartment s167
• (in auxiliary power center harness) s285
• (in auxiliary power center harness) s286
• (in auxiliary power center harness) s287
• 6j1
• 9l4
• Auxiliary power center (center of dash)
• Cicuit breaker 15a
• Cicuit breaker 25a
• Customer installed options
• From pwr wdo circuit breaker (diagram 2 of 5)
• From right battery (diagram 1 of 5)
• Fuse
• Fuse 150a
• Fuse 60a
• Fuse block
• Generator (police package)
• Mega fuse
• Pnk
• Police package
• Red
• Relay a
• Relay b
• Right battery
• S168
• S288
• S289

POWER DOOR LOCKS

Door Lock Wiring Diagram, without Crew Cab for GMC Cab & Chassis C1998 2500

List of elements for Door Lock Wiring Diagram, without Crew Cab for GMC Cab & Chassis C1998 2500:

• (inside right door harness) s601
• Convenience center (under left side of dash)
• G202 (below left side of dash)
• Hot at all times
• I/p fuse block (lower left side of dash)
• Left front door lock actuator
• Left front door lock switch
• Lock
• Pwr accy c.b. 20a
• Right front door lock actuator
• Right front door lock switch
• S255
• S500
• S600 (inside right door harness)
• Solid state
• Tan
• Unlock

Keyless Entry Wiring Diagram, without Crew Cab for GMC Cab & Chassis C1998 2500

List of elements for Keyless Entry Wiring Diagram, without Crew Cab for GMC Cab & Chassis C1998 2500:

• (crossbody harness, near door lock relay breakout) s256
• Batt (b+)
• C210
• Cig ltr fuse 13 20a
• Convenience center (left side of dash)
• Data link connector (under left side of dash)
• Dome lamps
• Dome lmp off
• Door lock relay (under center of dash, near remote control door lock receiver)
• Driver dr unlk
• G201 (right side of dash)
• Gauges fuse 4 10a
• Ground
• Horn signal
• Horns system
• Hot at all times
• Hot in run, bulb test or start
• I/p fuse block (left side of dash)
• Ignition
• Interior lamps system
• Left door lock switch
• Left front door lock actuator
• Lock
• Lock out
• Pass drs unlk
• Pnk
• Program sig
• Pwr accy c.b. 20a
• Remote control door lock receiver (under center of dash panel)
• Right door lock switch
• Right front door lock actuator
• S213
• S251
• S255
• S257 (crossbody harness, near door lock relay harness breakout)
• S258 (crossbody harn, under left side of dash)
• S260 (cross body harness, 6cm from seat belt switch breakout)
• S261 (crossbody harness, 12cm from seat belt switch breakout)
• S264
• Tan
• Unlock
• Unlock out
• W/ power windows
• W/o power windows

POWER MIRRORS

Photochromic Mirror Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Photochromic Mirror Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (behind left side of dash) g202
• Ambient sensor (windshield side)
• Automatic transmission
• Backup lamp switch (on left side of trans- mission)
• Backup lamp switch (part of park/neutral position switch) (on left side center of transmission)
• Breakout) s278
• C/m
• C1 f
• Exterior lights system
• Gauges fuse 4 10a
• Ground
• Headlamp sensor (mirror side)
• Hot in run or start
• I/p fuse block (under left side of dash)
• Inside automatic day-night mirror
• Left outside automatic day-night mirror
• Manual transmission
• Mirror input
• Mirrors switch
• Nca
• Note
• Off
• On indicator control
• Pnk
• Power distribution system
• Reset to daytime high reflectivity in reverse
• Right outside automatic day-night mirror
• S160 (see note)
• S213
• S279 (crossbody harness, approx 38 cm from convenience center pnk breakout)
• S316
• Si60: (4.3l) (engine harness, approximately 21 cm from egr valve breakout) s160: (5.0l & 5.7l) (engine harness, approximately 23 cm from ebcm breakout) s160: (6.5l) (engine harness, approximately 17 cm from ebcm breakout) s160: (7.4l) (engine harness approximately 28 cm from fuel injector breakout)
• Solid state
• T/m
• Temperature sensor (in engine compartment, near lower radiator support)
• Turn b/u fuse 16 20a

Power Mirrors Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Power Mirrors Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (inside left front door harness)
• (inside right front door harness)
• (right side of dash) g201
• Ctsy fuse 3 20a
• Down
• Hot at all times
• I/p fuse block
• Illum- nation lamp
• Interior lights system
• Left
• Left power outside rearview mirror
• Left/ right motor
• Power outside rearview mirror switch
• Red
• Right
• Right power outside rearview mirror
• S248
• S251
• S503
• S602
• Up/ down motor

POWER SEATS

6-Way Power Seat Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for 6-Way Power Seat Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (right side of dash)
• (w/ reg/extended cab) (except reg/extended cab)
• Back
• C210
• Convenience center
• Down
• Entire seat
• For- ward
• Forward/ rearward motor
• Front height
• Front tilt motor
• G201
• Hot at all times
• I/p fuse block
• Left power seat adjuster switch
• Pwr accy circuit breaker 20a 30a
• Rear height
• Rear tilt motor
• Right lumbar power seat switch
• Right power seat adjuster switch
• S237
• S255
• S259
• S303
• Tan

Heated Seats Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Heated Seats Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (cross body harn, left side of dash, near convenience center)
• (left heated seat harn, near heated seat control module breakout)
• Batt
• Convenience center
• Front heated seats fuse 20a
• G201 (right side of dash)
• Gnd
• Heated seat sw sig
• High/low sig
• Hot at all time
• Hot in run
• I/p fuse block
• Indicator lmp feed
• Left heated seat module (under left power seat)
• Left heated seat switch
• Off
• Power seat circuit
• Right heated seat module (under right power seat)
• Right heated seat switch
• Rr hvac fuse 5 10a
• S228
• S233
• S238
• S259
• S273
• S274
• S277
• S278
• S303
• Seat belt switch (on driver seat belt buckle)
• Seat cushion element
• Sig enable
• Thermistor
• Underhood fuse/relay center

Lumbar Wiring Diagram, Bench Seat for GMC Cab & Chassis C1998 2500

List of elements for Lumbar Wiring Diagram, Bench Seat for GMC Cab & Chassis C1998 2500:

• (right side of dash) g201
• (w/ regular/extended cab) (except regular extended cab)
• 6-way power seat circuit
• Convenience center (under left side of dash)
• Hot at all times
• I/p fuse block
• Left power lumbar support motor
• Left power seat lumbar switch
• Nca
• Power seat adjuster switch
• Pwr-accy circuit breaker 20a 30a
• Right power lumbar support motor
• Right power seat lumbar switch
• S227
• S259
• S303

Lumbar Wiring Diagram, Bucket And Split Bench with Heated Seat for GMC Cab & Chassis C1998 2500

List of elements for Lumbar Wiring Diagram, Bucket And Split Bench with Heated Seat for GMC Cab & Chassis C1998 2500:

• (right side of dash) g201
• 6-way power seat circuit
• Cig ltr fuse 13 20a
• Convenience center (under left side of dash)
• Hot at all times
• I/p fuse block
• Left power lumbar support motor
• Left power seat lumbar switch
• Nca
• Right power lumbar support motor
• Right power seat lumbar switch
• S259
• S264 (suburban utility only)
• S303

Lumbar Wiring Diagram, Bucket And Split Bench without Heated Seat for GMC Cab & Chassis C1998 2500

List of elements for Lumbar Wiring Diagram, Bucket And Split Bench without Heated Seat for GMC Cab & Chassis C1998 2500:

• C210 b
• Cig ltr fuse 13 20a
• Convenience center (under left side of dash)
• G201 (right side of dash)
• Hot at all times
• I/p fuse block
• Left power lumbar seat switch
• Pnk
• Power lumbar motor
• Right power lumbar seat switch
• S259
• S264 (suburban utility only)
• S310

POWER WINDOWS

Power Window Wiring Diagram, 2 Door for GMC Cab & Chassis C1998 2500

List of elements for Power Window Wiring Diagram, 2 Door for GMC Cab & Chassis C1998 2500:

• Auto window down module
• Convenience center (under left side of dash)
• Down
• G201 (right side of dash)
• Hot in run
• I/p fuse block (under left side of dash)
• Interior lights system
• Left front
• Left front window motor
• Left power window master switch
• Pwr window circuit breaker 30a
• Right front
• Right front window motor
• Right front window switch
• S251
• S259
• S266
• S500
• S501
• Solid state
• Tan

Power Window Wiring Diagram, 4 Door for GMC Cab & Chassis C1998 2500

List of elements for Power Window Wiring Diagram, 4 Door for GMC Cab & Chassis C1998 2500:

• (crossbody harn, approx 32cm from seat belt sw breakout toward i/p harn breakout)
• Convenience center (under left side of dash)
• Down
• Fuse block (under left side of dash)
• G201 (right side of dash)
• Headlamp and panel dimmer switch
• Hot at all times
• Hot in run
• Left front
• Left front power window master switch
• Left front window motor
• Left rear
• Left rear window motor
• Left rear window switch
• Pk lps fuse 20a
• Power window circuit breaker 30a
• Right front
• Right front window motor
• Right front window switch
• Right rear
• Right rear window motor
• Right rear window switch
• S247 (crossbody harn, approx 6cm into left door harn breakout)
• S251
• S259
• S263
• S500
• S501
• S502 (inside left front door harness, approx 4cm from tweeter breakout)
• Solid state
• Tan
• Window lockout switch

RADIO

Radio Wiring Diagrams, with Amplifier for GMC Cab & Chassis C1998 2500

List of elements for Radio Wiring Diagrams, with Amplifier for GMC Cab & Chassis C1998 2500:

• (left side of dash) data link connector
• (lf door harn, near window reg breakout)
• (rf door harn, near door lock motor breakout)
• Amp feed
• Antenna
• Audio rtn
• Bare
• Battery
• Cig ltr fuse 13 20a
• Diesel
• Dim
• Dim feed
• Display dim
• Drain rtn
• E&c diag
• Fuse out
• G201 (right side of dash)
• G202 (left side of dash)
• Gas
• Ground
• Hot at all times
• Hot in acc or run
• I/p fuse block
• Interior lights system
• Left front speaker
• Left front tweeter
• Left rear door speaker
• Left rear speaker
• Lf +
• Lf -
• Lr +
• Lr dr +
• Lr dr -
• Lr _
• Lr+
• Lr-
• Lt audio
• Lt remote
• Nca
• Pnk
• Power amplifier (under left side of dash)
• Power amplifier relay (under left side of dash)
• Radio
• Radio batt fuse 19 10a
• Radio fuse 17 10a
• Red
• Remote audio player
• Remote rtn
• Rf +
• Rf -
• Right front speaker
• Right front tweeter
• Right rear door speaker
• Right rear speaker
• Rly sig
• Rr +
• Rr -
• Rr dr +
• Rr dr -
• Rr+
• Rr-
• Rt audio
• Rt remote
• S221
• S249
• S250
• S251
• S252
• S254
• S256
• S259
• S298
• S504
• S505
• S603
• S604
• Serial data
• Tan
• Tape ctrl
• Vehicle control module (left side of engine compartment)
• Vehicle speed sensor buffer (behind right side of dash)
• Vss signal

Radio Wiring Diagrams, without Amplifier for GMC Cab & Chassis C1998 2500

List of elements for Radio Wiring Diagrams, without Amplifier for GMC Cab & Chassis C1998 2500:

• (left side of dash) data link connector
• (lf door harn, near window reg breakout)
• (rf door harn, near door lock motor breakout)
• Amp feed
• Antenna
• Audio rtn
• Bare
• Battery
• Diesel
• Dim
• Dim feed
• Display dim
• Drain rtn
• E&c diag
• Fuse out
• G202 (left side of dash)
• Gas
• Ground
• Hot at all times
• Hot in acc or run
• I/p fuse block
• Interior lights system
• Left front speaker
• Left front tweeter
• Left rear speaker
• Lf +
• Lf -
• Lr +
• Lr _
• Lt audio
• Lt remote
• Nca
• Pnk
• Radio
• Radio batt fuse 19 10a
• Radio fuse 17 10a
• Remote audio player
• Remote rtn
• Rf +
• Rf -
• Right front speaker
• Right front tweeter
• Right rear speaker
• Rr +
• Rr -
• Rt audio
• Rt remote
• S221
• S298
• S504
• S505
• S603
• S604
• Serial data
• Tan
• Tape ctrl
• Vehicle control module (left side of engine compartment)
• Vehicle speed sensor buffer (behind right side of dash)
• Vss signal

SHIFT INTERLOCKS

Shift Interlock Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Shift Interlock Wiring Diagram for GMC Cab & Chassis C1998 2500:

• Automatic transmission shift lock control (btsi) solenoid (right side of steering column)
• G202 (behind left side of dash)
• Hot in run or start
• I/p fuse block
• Park/ neutral position switch (left side of transmission)
• Pnk
• S204
• Transfer case control module (under dash on steering column support bracket)
• Turn/ hazard switch
• Turn/bu fuse 16 20a
• W/ electric shift transfer case

STARTING/CHARGING

Charging Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Charging Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (7.4l) l b
• (base)
• (gasoline)
• (gasoline-right front of engine, diesel-left front of intake manifold)
• (not used)
• (others)
• (right front wheelhouse)
• (uplevel)
• 175a
• Charge indicator
• Diesel only
• Fusible link (10 ga-rust)
• G101
• G119 (gasoline) g110 (diesel)
• Gauges fuse 4 10a
• Generator
• Hot in run, or start
• I/p fuse block
• Instrument cluster
• Left battery (diesel)
• Mega fuse block
• Pnk
• Power distribution system
• Power distribution system (diesel)
• Red
• Right battery
• S213
• Starting circuit
• Tach

Starting Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Starting Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (front of left front fender)
• (gas-right front of eng., diesel-left front of intake manifold)
• (right front off engine)
• (right front wheelhouse)
• 175a
• A/t
• Accy
• Battery stud
• Bulb test
• Charging circuit
• Clutch pedal position switch (top of clutch pedal)
• Crank fuse 8 10a
• Diesel
• G100
• G101
• G119
• G119 (gasoline) g110 (diesel)
• Gas
• Hold- in coil
• I/p fuse block
• Ign a fuse 6 40a
• Ignition switch
• Left battery (diesel)
• Lock
• M/t
• Mega fuse block (uplevel feature only)
• Nca
• Off
• Pull- in coil
• Red
• Right battery
• Run
• S107
• Start
• Starter motor
• Starter relay
• Starter solenoid
• Transmission range switch (left side of transmission)
• Underhood fuse-relay center

SUPPLEMENTAL RESTRAINTS

Supplemental Restraint Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Supplemental Restraint Wiring Diagram for GMC Cab & Chassis C1998 2500:

• (under left side of dash) data link connector
• Air bag fuse 10 10a
• Air bag ind
• Bar
• Cluster
• Dash fuse block (under left side of dash)
• Data line
• Driver high
• Driver low
• G202 (behind left side of dash)
• Gauges fuse 4 10a
• Ground
• Hot in run, bulb test or start
• Hot w/ headlamp switch in park or headlamp
• Ignition
• Illum fuse 14 10a
• Indicator lamp
• Inflatable restraint front end discriminating sensor (under front outside center of radiator)
• Inflatable restraint i/p module switch
• Inflatable restraint i/p module switch (right side of dash)
• Inflatable restraint sensing and diagnostic module (under driver's seat)
• Inflatable restraint steering wheel module (steering whl)
• Inflatable restraint steering wheel module coil
• Instrument
• Interior lights (dimmer swtch)
• Pass disable
• Pass enable
• Pass high
• Pass low
• Pnk
• S213 (dash harn, near breakout to steering column harn)
• S217 (dash harn, near breakout to radio harn)
• S218 (dash harn, near breakout to inflatable restraint sw)
• Seat belt sig
• Sensor feed
• Shorting
• Shorting bar
• Solid state
• Tan
• Warning systems (seat belt switch)

TRANSMISSION

5.0L

5.0L (VIN M), Transmission Wiring Diagram, 4L60-E for GMC Cab & Chassis C1998 2500

List of elements for 5.0L (VIN M), Transmission Wiring Diagram, 4L60-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (left side of transmission-2wd) (left side of transfer case-4wd)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 3-2 ctrl solenoid
• 3-2 downshift sol
• 4wd low signal in
• 5v reference
• Automatic transmission (4l60-e)
• Battery in
• Brake fuse 18 10a
• Brake switch input
• Dash fuse block
• Data class ii
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sens input
• Electronic brake control module
• Eng 1 fuse 20a
• Engine coolant temp sensor (top right front of engine)
• Front wheel lock
• Fuel injectors, ignition control moudule & ignition coil
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (top of right cylinder head)
• Gauges fuse 4 10a
• Hot at all times
• Hot in off, run or start
• Hot in run
• Hot in run or start
• Ignition in
• Instrument cluster
• Maf sensor & heated oxygen sensors
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Press ctrl solenoid
• Range signal "a"
• Range signal "b"
• Range signal "c"
• Red
• S101
• S103
• S108
• S150 (engine harn, 13 cm from bpmv break-out)
• S151
• S161
• S213
• S231 (engine harness, near map or egr break-out)
• Sensor ground
• Sensor return
• Solenoid
• Stoplamp switch (on brake pedal bracket)
• Tan
• Tcc
• Tcc pwm
• Tcc pwm sol
• Tcc sol
• Throttle position sensor (mounted to side of throttle body)
• Tp sens input
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range pressure switch assembly
• Trans range switches
• Trans temp sig in
• Transfer case & axle switches (4wd only)
• Transfer case circuit
• Underhood fuse/relay center
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor
• Vehicle speed sensor adaptor (4wd only)
• Vss hi
• Vss lo

5.7L

5.7L (VIN R), Transmission Wiring Diagram, 4L60-E for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Transmission Wiring Diagram, 4L60-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (left side of transmission-2wd) (left side of transfer case-4wd)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 3-2 ctrl solenoid
• 3-2 downshift sol
• 4wd low signal in
• 5v reference
• Automatic transmission (4l60-e)
• Battery in
• Brake fuse 18 10a
• Brake switch input
• Dash fuse block
• Data class ii
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sens input
• Electronic brake control module
• Eng 1 fuse 20a
• Engine coolant temp sensor (top right front of engine)
• Front wheel lock
• Fuel injectors, ignition control moudule & ignition coil
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (top of right cylinder head)
• Gauges fuse 4 10a
• Hot at all times
• Hot in off, run or start
• Hot in run
• Hot in run or start
• Ignition in
• Instrument cluster
• Maf sensor & heated oxygen sensors
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Press ctrl solenoid
• Range signal "a"
• Range signal "b"
• Range signal "c"
• Red
• S101
• S103
• S108
• S150 (engine harn, 13 cm from bpmv break-out)
• S151
• S161
• S213
• S231 (engine harness, near map or egr break-out)
• Sensor ground
• Sensor return
• Solenoid
• Stoplamp switch (on brake pedal bracket)
• Tan
• Tcc
• Tcc pwm
• Tcc pwm sol
• Tcc sol
• Throttle position sensor (mounted to side of throttle body)
• Tp sens input
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range pressure switch assembly
• Trans range switches
• Trans temp sig in
• Transfer case & axle switches (4wd only)
• Transfer case circuit
• Underhood fuse/relay center
• Vehicle control module (left side of engine compt)
• Vehicle speed sensor
• Vehicle speed sensor adaptor (4wd only)
• Vss hi
• Vss lo

5.7L (VIN R), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500

List of elements for 5.7L (VIN R), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (5.7l) (7.4l)
• (engine harn, 13 cm from bpmv break-out)
• (left rear side of transmission-2wd) (left side of transfer case-4wd)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 4wd low signal in
• 5v reference
• A/t iss hi in
• A/t iss lo in
• Automatic transmission (4l80-e)
• Automatic transmission input shaft speed sensor (on transmission)
• Battery in
• Brake fuse 18 10a
• Brake switch assembly (on brake pedal bracket)
• Brake switch input
• Data class ii
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sens input
• Electronic brake control module
• Eng 1 fuse 20a
• Engine coolant temp sensor (top right front of engine)
• Front wheel lock
• Fuel injectors, ignition control moudule & ignition coil
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (top of right cylinder head)
• Gauges fuse 4 10a
• Headlamp & panel dimmer switch
• Hot at all times
• Hot in run
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block
• Ignition in
• Instrument cluster
• Maf sensor & heated oxygen sensors
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Press ctrl
• Range signal "a"
• Range signal "b"
• Range signal "c"
• Red
• S101
• S103
• S108
• S150
• S151
• S161 s104
• S213
• S231 (engine harness, near map or egr breakout)
• Sensor ground
• Sensor return
• Solenoid
• Tan
• Tcc pwm
• Tcc pwm sol
• Throttle position sensor (mounted to side of throttle body)
• Tp sens input
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range pressure switch assembly
• Trans range switches
• Trans temp sig in
• Transfer case & axle switches
• Underhood fuse/relay center
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed sensor
• Vehicle speed sensor adaptor (4wd only)
• Vss hi
• Vss lo

6.5L

6.5L (VIN F), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN F), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (i/p harn, 4 cm from engine harn break-out)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 4wd low signal in
• A/t iss sens hi in
• A/t iss sens in
• A/t iss sens lo in
• A/t iss sensor out
• A12
• Accelerator pedal position module (part of accelerator pedal)
• App 1 5v ref
• App 1 signal in
• App 2 5v ref
• App 2 signal in
• App 3 5v ref
• App 3 signal in
• Automatic transmission
• Automatic transmission input shaft speed sensor (left front of transmission)
• B10
• B12
• Battery in
• Brake fuse 18 10a
• Brake switch assembly (on brake pedal bracket)
• Brake switch in
• C11
• C12
• C13
• C14
• C15
• Class ii data
• D11
• D12
• D13
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sensor in
• Engine coolant temp sensor (near thermostat housing)
• Front wheel lock
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (right top of cylinder head)
• Gauges fuse 4 10a
• Ground
• Hot at all times
• Hot in run
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block
• Ignition in
• Instrument cluster
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Power
• Powertrain control module (right side of dash near blower motor)
• Press ctrl
• Red
• S101
• S103
• S140 (engine sensor harness)
• S150 (engine harness, 13 cm from bpmv harness break-out)
• S152 (engine harn, 4 cm from i/p break-out)
• S211
• S213
• S220 (i/p harn, 12 cm from brake switch connector)
• S299
• Sensor ground
• Solenoid
• Stop/haz fuse 1 20a
• Stoplamp switch in
• Tan
• Tcc pwm
• Tcc pwm sol
• Tft sensor in
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range "a"
• Trans range "b"
• Trans range "c"
• Trans range pressure switch assembly
• Trans range switches
• Transfer case & axle switches
• Transfer case circuit
• Turn/ hazard switch & chime module
• Underhood fuse/relay center
• Vehicle speed sensor (on transmission-2wd) (on transfer case-4wd)
• Vehicle speed sensor (vss) adaptor (4wd only)
• Vehicle speed sensor buffer (right side of dash)
• Vss hi in
• Vss in
• Vss lo in
• Vss out

6.5L (VIN S), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500

List of elements for 6.5L (VIN S), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (i/p harn, 4 cm from engine harn break-out)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 4wd low signal in
• A/t iss sens hi in
• A/t iss sens in
• A/t iss sens lo in
• A/t iss sensor out
• A12
• Accelerator pedal position module (part of accelerator pedal)
• App 1 5v ref
• App 1 signal in
• App 2 5v ref
• App 2 signal in
• App 3 5v ref
• App 3 signal in
• Automatic transmission
• Automatic transmission input shaft speed sensor (left front of transmission)
• B10
• B12
• Battery in
• Brake fuse 18 10a
• Brake switch assembly (on brake pedal bracket)
• Brake switch in
• C11
• C12
• C13
• C14
• C15
• Class ii data
• D11
• D12
• D13
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sensor in
• Engine coolant temp sensor (near thermostat housing)
• Front wheel lock
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (right top of cylinder head)
• Gauges fuse 4 10a
• Ground
• Hot at all times
• Hot in run
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block
• Ignition in
• Instrument cluster
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Power
• Powertrain control module (right side of dash near blower motor)
• Press ctrl
• Red
• S101
• S103
• S140 (engine sensor harness)
• S150 (engine harness, 13 cm from bpmv harness break-out)
• S152 (engine harn, 4 cm from i/p break-out)
• S211
• S213
• S220 (i/p harn, 12 cm from brake switch connector)
• S299
• Sensor ground
• Solenoid
• Stop/haz fuse 1 20a
• Stoplamp switch in
• Tan
• Tcc pwm
• Tcc pwm sol
• Tft sensor in
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range "a"
• Trans range "b"
• Trans range "c"
• Trans range pressure switch assembly
• Trans range switches
• Transfer case & axle switches
• Transfer case circuit
• Turn/ hazard switch & chime module
• Underhood fuse/relay center
• Vehicle speed sensor (on transmission-2wd) (on transfer case-4wd)
• Vehicle speed sensor (vss) adaptor (4wd only)
• Vehicle speed sensor buffer (right side of dash)
• Vss hi in
• Vss in
• Vss lo in
• Vss out

7.4L

7.4L (VIN J), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500

List of elements for 7.4L (VIN J), Transmission Wiring Diagram, 4L80-E for GMC Cab & Chassis C1998 2500:

• (2wd only)
• (4wd only)
• (5.7l) (7.4l)
• (engine harn, 13 cm from bpmv break-out)
• (left rear side of transmission-2wd) (left side of transfer case-4wd)
• 1-2 shift sol
• 1-2 shift solenoid
• 2-3 shift sol
• 2-3 shift solenoid
• 4wd low signal in
• 5v reference
• A/t iss hi in
• A/t iss lo in
• Automatic transmission (4l80-e)
• Automatic transmission input shaft speed sensor (on transmission)
• Battery in
• Brake fuse 18 10a
• Brake switch assembly (on brake pedal bracket)
• Brake switch input
• Data class ii
• Data link connector (under left side of dash)
• Ecm 1 fuse 20a
• Ecm b fuse 20a
• Ect sens input
• Electronic brake control module
• Eng 1 fuse 20a
• Engine coolant temp sensor (top right front of engine)
• Front wheel lock
• Fuel injectors, ignition control moudule & ignition coil
• Fuel pump & oil press switch/ sender & fuel pump relay
• G120 (top of right cylinder head)
• Gauges fuse 4 10a
• Headlamp & panel dimmer switch
• Hot at all times
• Hot in run
• Hot in run or start
• Hot in run, bulb test or start
• I/p fuse block
• Ignition in
• Instrument cluster
• Maf sensor & heated oxygen sensors
• Malfunction indicator lamp
• Mil control
• Pcm ground
• Pcs sol hi out
• Pcs sol lo out
• Pnk
• Press ctrl
• Range signal "a"
• Range signal "b"
• Range signal "c"
• Red
• S101
• S103
• S108
• S150
• S151
• S161 s104
• S213
• S231 (engine harness, near map or egr breakout)
• Sensor ground
• Sensor return
• Solenoid
• Tan
• Tcc pwm
• Tcc pwm sol
• Throttle position sensor (mounted to side of throttle body)
• Tp sens input
• Trans fluid temp sensor
• Trans fuse 20 10a
• Trans range pressure switch assembly
• Trans range switches
• Trans temp sig in
• Transfer case & axle switches
• Underhood fuse/relay center
• Vehicle control module (vcm) (left side of engine compt)
• Vehicle speed sensor
• Vehicle speed sensor adaptor (4wd only)
• Vss hi
• Vss lo

WARNING SYSTEMS

Warning System Wiring Diagrams for GMC Cab & Chassis C1998 2500

List of elements for Warning System Wiring Diagrams for GMC Cab & Chassis C1998 2500:

• (behind left side of dash)
• (near thermostat housing)
• (opens with belt buckled)
• Audio alarm module (on convenience center)
• Diesel
• Fasten belts out
• G131
• G134 (front top of engine)
• G201 (right side of dash)
• G202
• Gas
• Gauges fuse 4 10a
• Ground
• Hot at all times
• Hot in park or headlight
• Hot in run, bulb test or start
• I/p fuse block (under left side of dash)
• Ignition on input
• Illum fuse 14 10a
• Instru- ment cluster
• Key-in warning
• Key-in warning buzzer switch (left side of steering column)
• Left door jamb switch
• Lights on input
• Pnk
• Power input
• S103
• S204
• S213
• S215
• S217
• S259
• S298
• S299
• Safety belts indicator
• Seat belt input
• Seat belt switch (in driver's safety belt buckle)
• Stop/haz fuse 1 20a
• Tan

WIPER/WASHER

Front Wiper/Washer Wiring Diagram for GMC Cab & Chassis C1998 2500

List of elements for Front Wiper/Washer Wiring Diagram for GMC Cab & Chassis C1998 2500:

• Front windshield washer pump motor
• G108 (left radiator support)
• G202 (behind left side of dash)
• Hot in accy or run
• I/p fuse block (under left side of dash)
• Inst wipe
• Low
• Mist
• Nca
• Off
• Pulse
• Red
• S158
• S204
• Solid state
• Wash
• Washer switch
• Windshield wiper motor module (on firewall, behind wiper motor)
• Windshield wiper/ washer switch
• Wiper fuse 11 25a
• Wiper switch