Diagram sections — 18 (80 total)
AIR CONDITIONING ANTI-LOCK BRAKES COMPUTER DATA LINES COOLING FAN CRUISE CONTROL ENGINE PERFORMANCE EXTERIOR LIGHTS GROUND DISTRIBUTION HEADLIGHTS HORN INSTRUMENT CLUSTER INTERIOR LIGHTS POWER DISTRIBUTION SHIFT INTERLOCKS STARTING/CHARGING TRANSMISSION WARNING SYSTEMS WIPER/WASHER
AIR CONDITIONING
4.3L 4.3L (VIN W), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998: 30 (engine harn, 13 cm from a/c compressor high pressure cutoff switch breakout) (engine harn, 30 cm from maf sensor breakout) (engine harness, near maf sensor) (provisions for body builder hvac system) A/c compressor clutch A/c compressor clutch relay (engine firewall relay bracket) A/c compressor high pressure cutoff switch (rear of a/c compressor) A/c compressor refrigerant pressure switch (a/c accumulator) A/c compressor refrigerant pressure switch (on a/c accumulator) A/c enable A/c ground A/c request Diode Eng-bat fuse 15a G112 (rear of left cylinder head) G200 (left interior bulkhead) Gauges fuse 20a Hot at all times Hot in run or start I/p fuse block Pnk R100 (engine harness, 30 cm from maf sensor breakout) S110 (engine harness, near bulkhead grommet) S124 S125 (engine harness, 13 cm from a/c high pressure switch breakout) S132 (engine harness, near maf sensor) S142 S143 S144 (engine harness, near firewall grommet) Vehicle control module (left side of engine compt)
5.7L 5.7L (VIN R), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998: 30 (engine harn, 13 cm from a/c compressor high pressure cutoff switch breakout) (engine harn, 30 cm from maf sensor breakout) (engine harness, near maf sensor) (provisions for body builder hvac system) A/c compressor clutch A/c compressor clutch relay (engine firewall relay bracket) A/c compressor high pressure cutoff switch (rear of a/c compressor) A/c compressor refrigerant pressure switch (a/c accumulator) A/c compressor refrigerant pressure switch (on a/c accumulator) A/c enable A/c ground A/c request Diode Eng-bat fuse 15a G112 (rear of left cylinder head) G200 (left interior bulkhead) Gauges fuse 20a Hot at all times Hot in run or start I/p fuse block Pnk R100 (engine harness, 30 cm from maf sensor breakout) S110 (engine harness, near bulkhead grommet) S124 S125 (engine harness, 13 cm from a/c high pressure switch breakout) S132 (engine harness, near maf sensor) S142 S143 S144 (engine harness, near firewall grommet) Vehicle control module (left side of engine compt)
6.5L 6.5L (VIN F), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998: 26 (body builder installed) (engine harn, near firewall grommet) (provisions for body builder hvac system) A/c compressor clutch A/c compressor control relay (right side of driver's island) A/c compressor high pressure cutoff switch (in high pressure line) A/c compressor refrigerant pressure switch (rear of a/c compressor) A/c enable A/c request Diode Eng-bat fuse 15a G206 (below driver's island) Gauges fuse 20a Hot at all times Hot in run I/p fuse block Pnk Powertrain control module (left side of driver's island) R100 (engine harness, 30 cm from maf sensor breakout) S115 (engine harness, near firewall grommet) S122 (engine harness, 20 cm from a/c compressor) S123 (engine harness, 25 cm from a/c compressor clutch) S140 S141 (engine harness, near firewall grommet) S168 S203 (i/p harness, near firewall grommet) 6.5L (VIN Y), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998: 17 (engine harn, 13 cm from a/c compressor high pressure cutoff switch breakout) (provisions for body builder hvac system) A/c compressor clutch A/c compressor clutch relay (engine firewall relay bracket) A/c compressor high pressure cutoff switch (rear of a/c compressor) A/c compressor refrigerant pressure switch (on a/c accumulator) Control module) Diode Eng-bat fuse 15a G200 (left interior bulkhead) Hot at all times I/p fuse block S125 (engine harness, 13 cm from a/c high pressure switch breakout) S144 (engine harness, 19 cm from a/c compressor clutch relay breakout) Vehicle control module (left side of engine compt) W/ vcm W/o vcm
7.4L 7.4L (VIN J), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Air Conditioning Wiring Diagrams for Chevrolet Forward Control P12 1998: 27 (body builder installed) (engine harn, 20 cm from cruise control module breakout) (provisions for body builder hvac system) A/c compressor clutch A/c compressor clutch relay (right side of driver's island) A/c compressor high pressure cutoff switch (rear of a/c compressor) A/c compressor refrigerant pressure switch (a/c accumulator) A/c enable A/c ground A/c request Diode Eng-bat fuse 15a G206 (below driver's island) Gauges fuse 20a Hot at all times Hot in run I/p fuse block Pnk R100 (engine harness, 30 cm from maf sensor breakout) S115 (engine harness, near firewall grommet) S122 (engine harness, 15 cm from a/c compressor) S123 (engine harness, 15 cm from a/c compressor clutch) S126 S140 S141 (iengine harness, near firewall grommet) S203 (i/p harness, near firewall grommet) Vehicle control module (center front of engine compt)
ANTI-LOCK BRAKES Anti-lock Brake Wiring Diagrams, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Anti-lock Brake Wiring Diagrams, Commercial Chassis for Chevrolet Forward Control P12 1998: 52 (ebcm harn, near right side of radiator) (i/p harn, above steering column) (i/p harn, left side of bulkhead) (left frame rail) (near steering column) data link connector (rear of left cylinder head) Abs ind Abs lamp control Brake diode d101 (underhood fuse-relay center) Brake ind Brake lamp control Brake pressure differential switch Brake sw input Brake sw output C1 tcc/ stoplamp switch Diesel Ebcm ground Electronic brake control module (below radiator of first crossmember) G100 G114 Gasoline Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I-3 fuse 15a 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 (-) S149 (i/p harn, 10 cm from before i/p fuse block breakout) S150 S154 S162 S167 S200 Serial data line Serial data signal Tan Vehicle control module (left side of engine compt) Vehicle speed sig Vss buffer (left side of interior bulkhead) Vss sig Anti-lock Brake Wiring Diagrams, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Anti-lock Brake Wiring Diagrams, Motor Home Chassis for Chevrolet Forward Control P12 1998: 48 (abs harn, near breakout to abs ground) (body builder installed) (i/p harn, above steering column) (i/p harn, left side of bulkhead) (near steering column) data link connector Abs ind Abs lamp control Brake diode d101 (underhood fuse-relay center) Brake ind Brake lamp control Brake pressure differential switch Brake sw input Diesel Ebcm ground Electronic brake control module (below radiator of first crossmember) Gasoline Gauges fuse 20a Hot at all times Hot in run Hot in run or start I-3 fuse 15a 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 (-) S150 S161 S162 S200 S207 S214 (i/p harn, left side of bulkhead) Serial data line Serial data signal Tan Tcc/ stoplamp switch Vehicle control module (left side of engine compt) Vehicle speed sig Vss buffer (left side of interior bulkhead) Vss sig
COMPUTER DATA LINES Computer Data Lines, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Computer Data Lines, Commercial Chassis for Chevrolet Forward Control P12 1998: 20 (body builder ground) B10 Data clss 2 Data link connector (below dash, near steering column) Diesel Electronic brake control module (below radiator, on first crossmember) Eng bat fuse 10 15a G114 (left rear of engine) Gasoline Hot at all times I/p fuse block S110 S143 S144 S150 (dash harn, approx 17 cm from breakout to steering column connector) S168 Serial data Tan Transmission control module (diesel a/t only) (on left interior firewall, on top of relay bracket) Vehicle control module (gasoline only) (4.3/5.7l: on left side of engine compt) (7.4l: on center front of engine compt) Computer Data Lines, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Computer Data Lines, Motor Home Chassis for Chevrolet Forward Control P12 1998: 18 (body builder ground) Data clss 2 Data link connector (below dash, near steering column) Diag sig Diesel Electronic brake control module (below radiator, on first crossmember) Eng bat fuse 10 15a Gasoline Hot at all times I/p fuse block Powertrain control module (on left side of driver's island) S141 S166 S202 (dash harness, 15 cm from vcm or abs harness breakout) S203 S212 Serial data Vehicle control module (on center front of engine compt)
COOLING FAN
6.5L 6.5L (VIN F), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998: 14 Auxiliary engine coolant fan a/c pressure switch (in a/c high pressure line) Auxiliary fan control switch Eng 1 fuse 20a Engine coolant fan motor Fan control relay (main support bracket, behind steering column) G200 (left interior bulkhead) Hot at all times Hot in run I/p fuse block Pnk Red S113 (engine harness, 5 cm from breakout for wiper motor) S128 (engine harness, 12 cm from glowplug control) S203 (i/p harness, 14 cm from firewall grommet) 6.5L (VIN Y), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998: 12 Auxiliary engine coolant fan Auxiliary engine coolant fan a/c pressure switch (in a/c high pressure line) Auxiliary engine coolant fan relay (engine firewall relay bracket, under battery junction block) Eng 1 fuse 20a G200 (left interior bulkhead) Hot at all times Hot in run and start I/p fuse block Pnk Red S110 (engine harness, 4 cm from electronic brake control module) S116 (engine harness, 5 cm from right glow plug breakout)
7.4L 7.4L (VIN J), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Cooling Fan Wiring Diagram for Chevrolet Forward Control P12 1998: 10 Auxiliary engine coolant fan a/c pressure switch (in a/c high pressure line) Eng bat fuse 15a Engine coolant fan motor Fan comntrol relay (main support bracket, behind steering column) G200 (left interior bulkhead) Hot at all times I/p fuse block Red S141 (engine harness, near firewall breakout) Vehicle control module (center front of engine compt)
CRUISE CONTROL
6.5L 6.5L (VIN F), Cruise Control Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Cruise Control Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 30 (engine harn, 16 cm from bulkhead grommet) (i/p harness, 8 cm from breakout for steering column) A11 B10 B11 Cruise on input D10 Disengage input Hazard lamps flasher Hot at all times Hot in run I-3 fuse 9 15a I/p fuse block Multifunction lever Nca Off Powertrain control module (pcm) (left side of driver's island) R/a Resume/accel input S/c S116 S124 S200 Set/coast input Stop/haz fuse 11 15a Stoplamp switch (top of brake pedal) Torque converter clutch and stoplamps switch (right side of steering column upper support) Vehicle speed sensor buffer (above accelerator pedal) Vss hi Vss lo
7.4L 7.4L (VIN J), Cruise Control Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Cruise Control Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 34 (engine harn, 11 cm from breakout to cruise module) (engine harn, 45 cm from breakout for map sensor) (rear of transmission) 4000 pulses/mile Cruise control module (radiator support bracket) Cruise control switch Cruise on input Cruise status Disengage input Ground Hazard lamps flasher Hot at all times Hot in run I-3 fuse 9 15a I/p fuse block Ignition Nca Off R/a Resume/accel input S/c S116 S124 S126 S200 Set/coast input Stop/haz fuse 11 15a Stoplamp switch (top of brake pedal) Torque converter clutch and stoplamps switch (right side of steering column upper support) Vehicle control module (vcm) (top of radiator support) Vehicle speed input Vehicle speed sensor (vss) Vss return Vss signal
ENGINE PERFORMANCE
4.3L 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998: 67 (on throttle body assembly) idle air control (iac) valve (right front of engine at crankshaft balancer pulley) (thermostat housing) g125 (top right side of engine) evaporative emissions (evap) canister purge solenoid valve 1-2 shift sol ctrl 2-3 shift sol ctrl 3x ckp sens sig A pnk Anti- lock brake system Cam posit sens rtn Cam posit sens sig Camshaft position (cmp) sensor (in distributor) Ckp sens rtn Crankshaft position (ckp) sensor Ect sensor input Egr posit input Evaporative emissions (evap) canister vent solenoid valve (left side of canister bracket) Feed ign a pnk Fuel inj no.1 ctrl Fuel inj no.2 ctrl Fuel inj no.3 ctrl Fuel inj no.4 ctrl Fuel inj no.5 ctrl Fuel inj no.6 ctrl Fuel lev G114 (rear of left cylinder head) Hall effect sensor Heated oxygen sensor bank 1, sensor 1 pre-convertor (left exhaust pipe ahead of catalytic converter) Ho2s bnk1 sens1 gnd Ho2s bnk1 sens1 sig Ho2s bnk2 sens1 gnd Ho2s bnk2 sens1 sig Ho2s post sens2 gnd Ho2s post sens2 sig Iat sens sig Idle air ctrl (a-low) Idle air ctrl (b-low) Idle air ctrl (iac) a-hi Idle air ctrl (iac) b-hi Knock sens sig Knock sensor (ks) (rear of engine, top center) Map sensor input Mass air flow input Nca Pnk Pnk c Pnk d Pnk pnk pnk Power Purge vent ctrl S138 S139 S140 S143 System ground Tan Tank press sens Tank pressure sensor (top of fuel tank) Tcc pwm sol ctrl Tft sig Throttle position sens Vehicle control module (vcm) (on left side of engine compartment) Vehicle speed out Vehicle speed sensor (vss) (left rear of transmission, near center) Vss rtn Vss sig Whl spd sig, left frt 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 35 (rear of left cylinder head) g114 (top front of engine) exhaust gas recirculation (egr) valve 1-2 shift solenoid 2-3 shift solenoid Automatic transmission (a/t) (if equipped) (rear of engine) Ecm 2 fuse 12 20a Eng 1 fuse 15 20a Fuel injector no.1 Fuel injector no.2 Fuel injector no.3 Fuel injector no.4 Fuel injector no.5 Fuel injector no.6 Heated oxygen sensor bank 2, sensor 1 (right exhaust pipe ahead of catalytic converter) Heated oxygen sensor, bank 1 sensor 2 (exhaust pipe behind catalytic converter) Hot in run & start I/p fuse block (dash panel provided by body builder) (body builder installed) Nca Pnk Pnk d Pnk n Pressure control solenoid (pcs) Red Red p Rev S108 S116 S118 S145 Tan Tan a Tcc pwm solenoid Trans fuse 17 10a Transmission fluid temperature (tft) sensor Transmission range (tr) pressure switch assembly 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 47 (eng harn, approx 13cm from tps breakout) (eng harn, approx 8cm from ect sensor breakout) (eng harn, approx 8cm from tps breakout) s136 (engine harn, 7 cm from ebcm breakout) (tail & stop lamps extension harness at crossmember in front of fuel tank) g415 5v ref A/c compressor high pressure cut-off switch (rear of a/c compressor) Eng bat fuse 10 15a Engine coolant temperature (ect) sensor (top front of engine) Fuel gauge Fuel pump switch & engine oil pressure gauge sensor (top left rear of engine) Fuel sender & fuel pump (top of fuel tank) G114 (rear of left cylinder head) G114 (rear of left cylinder head) Gauges fuse 8 10a Hot at all times Hot in run & start I/p fuse block (dash panel provided by body builder) (body builder installed) Instrument cluster Intake air temperature (iat) sensor (mounted in fresh air intake, behind filter box) Malfunction indicator lamp Manifold absolute pressure (map) sensor (top rear of engine) Map Mass air flow sensor (maf) (mounted in fresh air intake, behind air filter box) Nca Oil press gauge Pnk Pnk pnk pnk R100 (1100 ohms .75 watts) Red Ref lo S119 (eng harn, approx 11cm from ect sensor breakout) S135 S137 S138 S142 (eng harn, approx 23cm from maf sensor breakout) S144 S145 S207 S218 S406 Speedo meter Tacho meter Tan Tan a Temp Throttle position (tp) sensor (on throttle body, top of engine) 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Engine Performance Wiring Diagrams, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 70 (i/p harn, 17 17 cm from breakout to bulkhead conn) (i/p side of eng harn, approx 19cm from left bulkhead grommet toward ignition sw) (left interior bulkhead near relay bracket) (body builder installed) g202 (rear of left cylinder head) (rear of left cylinder head) g114 5v ref 5v return 87a A/c request sig A/c system A/t input speed sensor (transmission, left front) Anti-lock brakes system Brake sig Clutch pedal position switch (left side of brake pedal bracket) Clutch sig Cylinder no.1 Cylinder no.2 Cylinder no.3 Cylinder no.4 Cylinder no.5 Cylinder no.6 Data link connector (dlc) (partial) (below dash, near steering column) Distributor (top rear of engine) Ecm b fuse 6 20a Egr valve ctrl Evap can purge ctrl Feed ignition Fuel level Fuel pump prime connector (taped to fuel pump relay breakout) Fuel pump relay (on fire- wall, under battery junction block) Fuel pump rly ctrl G114 Ground High voltage coil wire Hot at all times Hot in run I-3 fuse 9 15a I/p fuse block (dash panel provided by body builder) (body builder installed) Ign feed Ignition coil (top right side of engine) Ignition control module (right top of engine) Input spd sens rtn Input spd sens sig Mil ctrl Pcs sol (hi) Pcs sol (lo) Pnk Pnk a Pressure switch in Range sig "a" Range sig "b" Range sig "c" Red Relay ctrl Return control S133 S134 S138 S143 S150 S200 Serial data Shift interlock system Signal control timing Spark plugs System ground Tcc/stop lamps switch (right side of steering column upper support) Timing ctrl sig Vehicle control module (vcm) (left side of engine compartment) Vss output
5.7L 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998: 68 (left side of air intake system) idle air control (iac) valve (right center of intake manifold) evaporative emissions (evap) canister purge solenoid valve (right front of engine at crankshaft balancer pulley) crankshaft position sensor (ckp) 1-2 shift sol ctrl 2-3 shift sol ctrl 4x ckp sens sig A pnk Anti-lock brake system C pnk Cam posit sens rtn Cam posit sens sig Camshaft position (cmp) sensor (in distributor) Ckp sens rtn Ect sensor in Egr posit in Evaporative emissions (evap) canister vent solenoid valve (left side of canister bracket) Fuel inj no.1 ctrl Fuel inj no.2 ctrl Fuel inj no.3 ctrl Fuel inj no.4 ctrl Fuel inj no.5 ctrl Fuel inj no.6 ctrl Fuel inj no.7 ctrl Fuel inj no.8 ctrl Fuel lev signal G114 (rear of left cylinder head) Hall effect sensor Heated oxygen sensor, bank 1 sensor 2 (left exhaust pipe ahead of catalytic converter) Heated oxygen sensor, bank 2 sensor 1 (right exhaust pipe ahead of catalytic converter) Ho2s bnk1 sens1 gnd Ho2s bnk1 sens1 sig Ho2s bnk1 sens2 gnd Ho2s bnk1 sens2 sig Ho2s bnk2 sens1 gnd Ho2s bnk2 sens1 sig Ho2s bnk2 sens2 gnd Ho2s bnk2 sens2 sig Iat sens sig Idle air ctrl (a-low) Idle air ctrl (b-low) Idle air ctrl (iac) a-hi Idle air ctrl (iac) b-hi Knock sens sig Knock sensor (ks) (lower right side of engine) Map sensor in Mass air flow in Nca Pnk Pnk d Pnk pnk Pnk pnk pnk Power Purge vent S138 S139 S140 Tan Tan a Tank pressure Tank pressure sensor (top of fuel tank) Tcc pwm sol ctrl Tft sig Throttle posit sens Vehicle control module (vcm) (left side of engine compt) Vehicle speed out Vehicle speed sensor (vss) (left rear of transmission, near center) Vss rtn Vss sig 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 29 (rear of left cylinder head) g114 1-2 shift solenoid 2-3 shift solenoid Automatic transmission (a/t) (if equipped) (rear of engine) Ecm-1 fuse 12 20a Eng 1 fuse 15 20a Exhaust gas recirculation (egr) solenoid valve (front left top of intake manifold) Fuel injector Heated oxygen sensor, bank 1 sensor 2 (left exhaust pipe behind catalytic converter) Heated oxygen sensor, bank 2 sensor 2 (right exhaust pipe behind catalytic converter) Hot in run & start I/p fuse block (dash panel provided by body builder) (body builder installed) Nca Pnk Pnk d Pnk n Pressure control solenoid (pcs) Red Red p Rev S108 S116 S118 S145 Tan Tan a Tcc pwm solenoid Transmission fluid temperature sensor Transmission range (tr) pressure switch assembly 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 45 (eng harn, approx 30cm from maf sensor breakout) (eng harn, approx 8cm from ect sensor breakout) s135 (eng harn, approx 8cm from tp sensor breakout) (rear of left cylinder head) g114 (tail & stop lamps extension harness at crossmember in front of fuel tank) g415 5v ref A/c compressor high pressure cut-off switch (rear of a/c compressor) Eng-b fuse 10 15a Engine coolant temperature (ect) sensor (top front of engine) Fuel gauge Fuel pump switch & engine oil pressure gauge sensor (top left rear of engine) Fuel sender & fuel pump (top of fuel tank) G114 (rear of left cylinder head) Gauges fuse 8 20a Hot at all times Hot in (on) run & start (crank) I/p fuse block (dash panel provided by body builder) (body builder installed) Instrument cluster Intake air temperature (iat) sensor (in fresh air intake, behind air filter box) Manifold absolute pressure (map) sensor (top right rear of engine) Map Mass air flow (maf) sensor (in fresh air intake behind air filter box) Nca Oil press gauge Pnk R100 (1100 ohms .75 watts) Red Ref lo S119 (eng harn, approx 4cm from ect sensor breakout) S136 S137 (eng harn, approx 12cm from tp sensor breakout) S138 S142 S144 S145 S207 S218 Service engine soon indicator Speedo meter Tacho meter Tan Tan a Temp Throttle position (tp) sensor (throttle body, top of engine) Trans fuse 17 10a 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Engine Performance Wiring Diagrams, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 76 (below dash, (i/p harn, above steering column) (i/p side of eng harn, approx 19cm from left bulkhead grommet) (left interior bulkhead near relay bracket) (body builder installed) g202 (rear of left cylinder head) (rear of left cylinder head) g114 5v ref 5v rtn 87a A/c compressor enable A/c request sig A/c sw in A/c system A/t input speed sensor (transmission, left front) Anti-lock brake system Brake sig Clutch pedal position switch (top of clutch pedal support) Clutch sig Cylinder 1 Cylinder 2 Cylinder 3 Cylinder 4 Cylinder 5 Cylinder 6 Cylinder 7 Cylinder 8 Data link connector (dlc) Distributor (top rear of engine) Ecm-b fuse 6 20a Egr ctrl Evap canp valve driver Fuel lev Fuel pump a prime connector (taped to fuel pump relay breakout) Fuel pump relay (engine bulkhead relay bracket under battery junction block) Fuel pump rly ctrl G114 Gnd Ground High voltage coil wire Hot at all times Hot in run I-3 fuse 9 15a I/p fuse block (dash panel provided by body builder) (body builder installed) Ign feed Ignition coil (top right side of engine) Ignition control module (bracket at top edge of right cylinder head) Ignition feed Input spd sens rtn Input spd sens sig Mil ctrl Near steering column) Pcs sol (hi) Pcs sol (lo) Pnk Pnk a Range sig "a" Range sig "b" Range sig "c" Red S110 S133 S134 S138 S143 S150 S200 Serial data Shift interlock system Spark plugs System gnd Tcc/ stop lamps switch (right side of steering column upper support) Timing control return Timing control signal Timing ctrl sig Vehicle control module (vcm) (left side of engine compt) Vss output
6.5L 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 40 (at rear of brake pedal support bracket) 5 volt ref Accelerator pedal position module (attached to accelerator pedal) App 1 sensor App 2 sensor App 3 sensor B fuel sol ctrl B pump cam sig Brake transmission shift interlock (btsi) relay (mounted on top of support bracket at driver's island) C closure grd C high res sig Closure signal D ignition D sensor ground Engine shutoff solenoid F4 i-3 fuse 9 15a f3 Fuel sol high Fuel sol low Fuel sole- noid Fuel solenoid driver (top left of engine) G6 ecm-1 fuse 12 20a g5 Haz fuse 11 15a Hazard flasher (inner left side of main support bracket) High Hot at all times Hot in run Hot in run and start I/p fuse block Ignition timing stepper motor (part of fuel injection pump) J6 trans fuse 17 10a j5 Low Optical fuel temperature sensor (part of fuel injection pump) Pnk Red S116 S121 S124 (eng harn, 16 cm from left bulkhead grommet toward pcm) S200 (i/p harn, 8 cm from breakout for steering column) Stop/ g7 Tcc/ stoplamp switch 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 40 (17 cm from rear/lamp harness) g415 (18 cm from breakout for left glow plugs) g112 (18 cm from breakout for left glow plugs) g112 87a A/c compressor clutch relay (right side of driver's island) A/c high pressure cut-off switch (on rear of the a/c compressor) Ecm-b fuse 6 20a Eng bat fuse 10 15a Fuel lift pump (inside right frame rail, ahead of fuel tank) Fuel pump prime connector Fuel pump relay (in underhood fuse/relay center) Fuel pump switch and engine oil pressure gauge switch (left rear of engine) G114 (rear of left cyl head) Gauges fuse 8 20a Hot at all times Hot in run and start I/p fuse block Instrument cluster Malfunction indicator lamp (mil) Nca Oil press gauge Pnk Red S114 S115 S126 S132 S140 (eng harn, 35 cm from pcm conns, toward left firewall grommet) S141 S143 S154 S168 S400 Service throttle soon indicator Speed meter Tan Wait to start indicator Water in fuel indicator Water in-fuel indicator sensor (part of fuel/water separator (filter) rear of intake manifold) Water in-fuel input 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Engine Performance Wiring Diagrams, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 67 "serv throttle soon" ind (dlc) (partial) (below dash, near steering column) (eng harn, 21 cm from breakout for generator) s144 (eng harn, 7 cm from main harn in breakout for glowplugs) s145 A/c enable Antilock brakes system App 2 5 volt ref Battery Breakout) s200 C10 C11 C12 C13 C14 C15 C16 D10 D11 D12 D13 D14 D15 D16 Data link connector Eng-1 h6 Eso ctrl Eso solenoid ctlr Fuel heater (top rear of engine) Fuel inject ctrl Fuse 15 20a Fusible link Fusible links G114 (left rear of engine block) G202 (left side of dash) 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 out Glow plug relay (top rear of intake manifold) Ground Hot at all times Hot in run and start I/p fuse block Ignition Mil ind ctrl Nca Pnk Powertrain control module (pcm) (left side of driver's island) Red Relay ctrl S128 S135 S163 (eng harn, 21 cm from left fire- wall grommet toward pcm) S166 S203 Serial data sig Shift sol 1-2 input Shift sol 2-3 input Tcc pwm sol vlv ctrl Wait to start ind ctrl Wastegate sol ctrl Wastegate solenoid 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (1 of 4) for Chevrolet Forward Control P12 1998: 97 (a/t) (rear of left cylinder head) (center rear of intake manifold) manifold absolute pressure sensor (eng harn, 4cm from breakout to glowplug controller) (eng harn, at battery junction block) (eng harn, near left bulkhead grommet) (front of engine, in air intake) intake air temperature sensor (left front side of left cyl head) engine coolant temperature sensor (lower left front of engine) crankshaft position sensor (m/t) (on generator bracket) 12v 3-2 shift sol 5v ref volt A/c request sig A/t input speed sensor (left side of transmission) A10 A11 A12 Air conditioning App no.1 gnd App no.1 ref volt App no.1 sig App no.2 gnd App no.2 sig App no.3 gnd App no.3 ref volt App no.3 sig Automatic transmission (a/t) B10 B11 B12 Brake sw in Brake switch input C10 C11 C12 C13 C14 C15 C16 Cam posit sens sig rtn Camshaft posit sens Closure gnd D10 D11 D12 D13 D14 D15 D16 Ebcm Ect temp sens in Electronic brake control module (below radiator, on crossmember) Engine crank sens input Force motor Force mtr hi Force mtr low Fuel pump input Fuel pump rly ctrl Fuel sol closure (5v sig) Fuel temp sens (5v sig) G114 Glow plug "wait" lp out Glow plug relay Ground Intake air temp sens Map sensor Pcs low Pnk Powertrain control module (pcm) (left side of driver's island) Range mode sel a Range mode sel b Range mode sel c Range mode selector Red S119 S143 S160 S162 Second vss sig Sensor gnd Shift sol a Shift sol b Solid state Speed sensor hi Speed sensor lo Tan Timing stepper mtr (high) Timing stepper mtr (low) Transmission speed input Transmission temp input Transmission temperature sensor Vehicle speed sensor (left rear of transmission) Vehicle speed sensor buffer (on driver's island support above accelerator pedal) Vss hi Vss lo Vss rtn Vss sig 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (2 of 4) for Chevrolet Forward Control P12 1998: 31 Accelerator pedal position module (attached to accelerator pedal) App 1 sensor App 2 sensor App 3 sensor Brake transmission shift interlock (btsi) relay (mounted on top of support bracket at driver's island) Engine shutoff solenoid F4 i-3 fuse 9 15a f3 Fuel sole- noid Fuel solenoid driver Fuel temp. G6 ecm-1 fuse 12 20a g5 Haz fuse 11 15a Hazard lamps flasher (behind left side of dash, above steering column) High Hot in run Hot in run or start I/p fuse block (behind dash panel, body builder installed) Injection pump (top front of engine) J6 trans fuse 17 10a j5 Low Optical 3 temperature sensor Pnk Red S108 S116 S124 (eng harn, 13cm from breakout to a/c cutoff switch) S200 (dash side of engine harn, 15cm from bulkhead grommet) Stop lamps & torque converter brake switch (opens w/brake pedal depressed) (at rear of brake pedal support bracket) Stop- g7 Stoplamp switch (at rear of brake pedal support bracket) Timing stepper motor 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (3 of 4) for Chevrolet Forward Control P12 1998: 29 (a/t) (rear of left cylinder head) (m/t) (on generator bracket) (tail & stoplamp extension harn, at crossmember in front of fuel tank) g415 87a Ecm- bat fuse 6 20a Fuel lift pump (inside left frame rail, below driver's door) Fuel pump oil pressure indicator switch (left rear of engine) Fuel pump relay (under battery junction box) G114 Gauges fuse 8 20a Hot at all times Hot in run or start I/p fuse block (behind dash panel, body builder installed) In line to fuel pump prime (plant use) Instrument cluster Oil press gauge Pnk Red S118 S170 S171 (eng harn, 50cm from breakout to elctronic brake control module) S207 S406 Service engine soon indicator Service throttle soon indicator Speed meter Tan Wait to start "glow plugs" indicator Water in fuel indicator 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Electronic (4 of 4) for Chevrolet Forward Control P12 1998: 57 "serv eng soon" ind "serv throttle soon" ind (a/t) (rear of left cylinder head) (at fuel filter assembly) fuel heater (eng harn, 21cm from breakout to generator) s144 (eng harn, 21cm from breakout to generator) s145 (left rear of engine near firewall) glow plug control module (m/t) (on generator bracket) (part of fuel/water seperator (filter), rear of intake manifold) water in fuel indicator sensor 12v battery (fused) 12v battery fused 3/2 ctrl out A/c enable Air conditioning App no.2 ref voltage C10 C11 C12 C13 C14 C15 C16 D10 D11 D12 D13 D14 D15 D16 Data link connector (below dash, near steering column) Electronic brake control module (below radiator, on first crossmember) Eng-1 h6 Engine shutoff sol out Fuel sol module (5 vref) Fuel sol module feed Fuse 15 20a Fusible links G114 Hot at all times Hot in run or start I/p fuse block (behind dash panel, body builder installed) Ignition Left bank glow banks Nca Pcm gnd Pnk Powertrain control module (pcm) (left side of driver's island) Red Right bank glow banks S116 S118 S143 S150 (dash harn, near steering column upper support) S163 (eng harn, 21cm from breakout to left bulkhead grommet) Serial data sig Shift sol a input Shift sol b input 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (1 of 3) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (1 of 3) for Chevrolet Forward Control P12 1998: 85 (eng harn, approx 6cm from breakout to glowplug control switch) (left side of trans) a/t input speeed sensor (rear of left cylinder head) g114 1-2 shift sol ctrl 2-3 shift sol ctrl 5v ref A10 A11 A12 A6 a8 B10 B11 B12 Baro press sens sig Barometric pressure (baro) sensor (top left rear of intake manifold) Battery feed Brake pedal sw in Brake/transmission shift interlock relay (on top of driver's island support bracket) C10 C11 C12 C13 C14 C15 C16 D10 D11 D12 D13 D14 D15 D16 Data link connector (partial) (below dash, near steering column) Ebcm Ecm-1 fuse 12 20a Ecm-bat fuse 6 20a Electronic brake control module (below radiator, on first crossmember) Eng speed sens in Engine speed sensor (top front of engine, in fuel injection pump) G114 (rear of left cylinder head) Ground Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block (behind dash panel) (body builder installed) Ign feed Pnk Press ctrl sol (hi) Press ctrl sol (lo) Range signal a Range signal b Range signal c Red Ref 5 volt Rtn S108 S111 (eng harn, approx 10cm from breakout to generator jumper) S116 S119 S143 S170 S200 (dash side of eng harn, approx 15cm from left bulkhead grommet) Sensor return Serial data Service trans out Sig sensor Speed sensor Stoplmp sw in Tan Tcc pwm sol ctrl Tcm ground Tft sig Throttle position sensor (tps) (right side of fuel injection pump) Torque converter clutch (tcc) & stop lamps switch (opens w/brake pedal depressed) (right side of steering column upper support) Tp sens sig Transmission control module (tcm) (left interior bulkhead on top of relay bracket) Vehicle speed sensor (vss) (left side of trans) Vehicle speed sensor (vss) buffer (on driver's island support, above accelerator pedal) Vehicle speed sig Vss Vss input Vss out Vss rtn Vss sig 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (2 of 3) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (2 of 3) for Chevrolet Forward Control P12 1998: 39 "wait to start" glow plugs (a/t - rear of left cyl head) (m/t - on generator bracket) (taped to fuel pump relay breakout) fuel pump prime connector 1-2 shift solenoid 2-3 shift solenoid Automatic transmission (a/t) (rear of engine) Ecm-1 fuse 12 20a Ecm-bat fuse 6 20a Engine oil pressure gauge sensor (on top left rear of eng block) Fuel injection pump fuel shutoff solenoid (at fuel injection pump) Fuel pump motor Fuel pump relay (on engine firewall bracket, under battery junction block) G114 G114 (rear of left cylinder head) Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I/p fuse block (behind dash panel) (body builder installed) Instrument cluster Oil gauge Orn Pnk Pressure control solenoid Red S108 S118 S143 S170 S171 S207 Service trans Speedo meter Tan Tcc pwm solenoid Trans fuse 17 10a Transmission fluid temperature (tft) sensor Transmission range (tr) pressure switch assembly Water in- fuel 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (3 of 3) for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Engine Performance Wiring Diagrams, Commercial Chassis - Mechanical (3 of 3) for Chevrolet Forward Control P12 1998: 51 (a/t) (m/t) (on generator bracket) left cylinder head) (eng harn, 12cm from breakout to right glow plugs) s117 (eng harn, near breakout to glow plug control sw) s122 (rear of 10a A/t Acc Battery junction block (on top left rear of intake manifold) Clutch pedal position (cpp) switch (closed with clutch pedal depressed) (on top of clutch pedal support) Crank fuse (engine harness, right of steering column) Crk (start) D100 (engine harn, approx 13cm from breakout to a/c compressor high press cutoff sw) Eng-1 fuse 15 20a Fuel heater (at fuel filter assembly) Fuel injection pump cold advance solenoid (in fuel injection pump) Fuel injection pump cold advance solenoid/ engine coolant temperature switch (on rear of right cylinder head) G114 G200 (left interior bulkhead, near relay bracket) Glow plug control switch (rear of left cylinder head) Glow plug ctrl Glow plug stud Glow plug tell tale relay (on relay bracket. left sdie of interior bulkhead) Ground Hot at all times Hot in run or start I/p fuse block (behind dash panel) (body builder installed) Idle speed control solenoid actuator (on front of fuel injection pump) Ign feed Ignition switch Ind lamp out Left bank glowplugs (on cylinder heads, below valve covers) Lock M/t Off On (run) Park/neutral position (pnp) & backup lamps switch (closed in park or neutral) (left side near middle of transmission) Pnk Red Right bank glowplugs (on cylinder heads, below valve covers) S stud S109 (eng harn, approx 33cm from left bulkhead grommet) S110 S115 S116 S135 S172 (eng harn) Starter feed Starter relay (on eng firewall relay bracket, under battery junction block) Starter solenoid (on starter, at lower right side of engine) Stud Water in-fuel sensor (part of fuel/water separator (filter) at rear of intake manifold)
7.4L 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (1 of 4) for Chevrolet Forward Control P12 1998: 54 (left rear side of transmission) a/t output speed sensor (on lower right front of engine, behind torsional damper) crankshaft position sensor (on throttle valve assembly) idle air control valve 1-2 shift sol ctrl 1x cmp sig 2-3 shift sol ctrl 4x ckp sig A pnk Anti- lock brakes system Camshaft position sensor (internal to distributor) Ckp low Cmp low Ect signal Egr posit input Fuel gauge Heated oxygen sensor (ho2s) bank 2 sensor 1 (on right exhaust pipe before catalytic converter) Ho2s high Ho2s low Iac a high Iac b high Iac high Iac low Iat signal Ign feed Injector 1 ctrl Injector 2 ctrl Injector 3 ctrl Injector 4 ctrl Injector 5 ctrl Injector 6 ctrl Injector 7 ctrl Injector 8 ctrl Ks signal Left knock sensor (on lower left side of engine) Maf signal Map signal Nca Pnk Pnk d Pwm tcc sol ctrl Right knock sensor (on lower right side of engine) S131 (eng harn, 13 cm from breakout for egr, toward map sensor) Sens rtn Sens sig Sensor rtn Sensor signal Tan Tan a Tft signal Tp signal Vehicle control module (vcm) (center front of engine compartment) Vss Vss low Vss signal 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 41 Automatic transmission Ecm-1 fuse 12 20a Eng-1 fuse 15 20a Exhaust gas recirculation valve solenoid (left side of intake plenum) Fluid temperature sensor (internal) Force motor Fuel inj 1 Fuel inj 2 Fuel inj 3 Fuel inj 4 Fuel inj 5 Fuel inj 6 Fuel inj 7 Fuel inj 8 G117 (13 cm from breakout for ignition coil) Heated oxygen sensor (ho2s) bank 1 sensor 1 (on left exhaust pipe before catalytic converter) Heated oxygen sensor (ho2s) bank 1 sensor 2 (on left exhaust pipe after catalytic converter) Heated oxygen sensor (ho2s) bank 2 sensor 2 (on right exhaust pipe after catalytic converter) Hot in run and start I/p fuse block Ignition Intake air temp sensor (mounted in fresh air intake behind air filter box) Nca Pnk Pnk d Pnk e Pnk n pressure Pnk pnk Red Red p pressure S121 S133 S135 S158 S159 Solenoid 1-2 Solenoid 2-3 Switch Tan Tan a Toward eng) 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 38 (10 cm from breakout for generator) g120 (17 cm from rear lamp harness) g415 (eng harn, 20 cm from breakout for cruise control module, toward vcm) (eng harn, 4cm from breakout for cruise control module, toward relays) (eng harn, 7 cm from breakout for left front wheel speed sensor, toward eng) s127 A/c compressor high pressure cut-off switch (on rear of a/c compressor) Eng-bat fuse 10 15a f1 Engine coolant temperature sensor (on top front of engine) Fuel gauge Fuel pump and fuel tank sender (on top of fuel tank) Fuel pump/ oil pressure switch (on top left rear of engine) G120 (10 cm from breakout for generator) Gauges fuse 8 20a Hot at all times Hot in run and start I/p fuse block Instrument cluster Malfunction indicator lamp (mil) (service engine soon) Manifold absolute pressure (map) sensor (top center front of engine) Mass air flow sensor (right front of engine comp, on air intake assembly) Nca Oil press gauge Pnk Red S119 (eng harn, 4 cm from breakout for generator, toward cruise control module) S120 S126 S132 S140 S141 S154 S165 S400 Speed meter Tach Tan Throttle position sensor (on throttle body, top of engine) Trans fuse 17 10a 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Engine Performance Wiring Diagrams, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 81 (10 cm from breakout for generator) g120 (i/p harn, 15 cm from breakout for abs harn) s202 87a A/c comp cyl sw A/c rec A/c relay A/c request signal Air conditioning system Anti-lock brakes system Automatic transmission input shaft speed sensor (left side of transmission) Aux elect cooling fan B + Battery feed Brake signal Brake/transmission shift interlock (btsi) relay (mounted on top of support bracket at driver's island) Check engine lp ctrl Cooling fans system Cruise control module (on radiator support bracket) Cruise ctrl engaged Cruise engaged sig Cylinder 1 Cylinder 2 Cylinder 3 Cylinder 4 Cylinder 5 Cylinder 6 Cylinder 7 Cylinder 8 Data link connector (dlc) (below dash, near steering column) Distributor Ecm-b fuse 6 20a Egr valve feed Egr vlv ctrl Egr/map 5v ref Elec spk timing ctrl signal Est ctrl Evaporative emission canister purge valve (top left center of engine, behind a/c compressor) Fuel level module Fuel pmp rly ctrl Fuel pump prime connector Fuel pump relay (left side of engine compt) G114 (left rear of engine block) G120 (engine) (10 cm from breakout for generator) G202 (below left side of dash) Ground High voltage coil wire Hot at all times Hot in run I-3 fuse 9 15a I/p fuse block Ic cntrl Ign feed Ignition coil (on bracket at rear of intake plenum) Ignition coil module (on bracket at rear of intake plenum) Input speed sens high Input speed sens low Pcs high Pcs low Pnk Pnk a Purge canister sol Range signal a Range signal b Range signal c Red S114 S116 S126 S166 S200 (eng harn, 45 cm from breakout for map sensor, toward firewall) S203 Sens ground Sensor ground Serial data Spark plugs Speed sensor input Tcc stoplamp switch (opens w/brake depressed) (right side of steering column upper support) Tcc/stoplamp input Tp sig 5v ref Vehicle control module (vcm) (on center front of engine compartment) Vss output signal
EXTERIOR LIGHTS Back-up Lamps Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Back-up Lamps Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 11 (left side of transmission) backup lamps switch A/t Hot in run I/p fuse block M/t Park/neutral position (pnp) & backup lamp switch (left side of transmission) Provision for left backup lamp Provision for right backup lamp S403 (rear lamps harness, 65 or 120cm rearward of taillamps extension to rear lamps harness breakout) Turn b/u fuse 5 15a Turn signal flasher (i/p fuse block) Back-up Lamps Wiring Diagram, Motorhome Chassis for Chevrolet Forward Control P12 1998 List of elements for Back-up Lamps Wiring Diagram, Motorhome Chassis for Chevrolet Forward Control P12 1998: 8 Hot in run I/p fuse block Park/neutral position (pnp) & backup lamp switch (left side of transmission) Provision for backup lamps (on left frame rail near rear lamp harness) Provision for rear mounted camera (near breakout for steering column harness) S134 (engine harn, near breakout for starter motor) Turn b/u fuse 5 15a Turn signal flasher (i/p fuse block) Exterior Lamps Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Exterior Lamps Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 48 (dash harness headlamp switch breakout, 8cm before i/p fuse block breakout) s208 (forward lamps harn, 4cm from horn conn breakout) s101 (rear lamps harness, 55 or 110cm from tail/ stoplamps extension harness to rear lamps harness, near left frame rail and fuel tank) s402 Backup lamps circuit C205 provisions for marker lamps (near i/p fuse block) G114 (left rear of engine) Hazard Hazard lamps flasher (left inner bulkhead on relay bracket) Head Headlamps switch Hot at all times Hot in run I/p fuse block Instrument cluster Interior lamps system Left front park & turn signal (t/s) lamp Left front side marker lamp Left rear license lamps Left turn ind. Normal Off Park Provision for center high mounted stop lamp Provisions for left rear side marker lamp Provisions for left tail/stop & turn signal lamps Provisions for right rear side marker lamp Provisions for right tail/stop & turn signal lamps Right front park & turn signal (t/s) lamp Right front side marker lamp Right rear license lamps Right turn ind. S101 (forward lamps harn, 4cm from horn conn breakout) S104 (forward lamps harn, 15cm after right lamps breakout) S105 (forward lamps harn, 10cm before right lamps breakout) S218 S404 (rear lamps harness, 5cm from right tail- lamps breakout) S405 (rear lamps harness, 5cm from left taillamps breakout) Stop Stop haz fuse 11 15a Tail Tail lamps fuse 7 20a Torque converter clutch & stop lamps switch (right side of steering column upper support) Turn Turn b/u fuse 5 15a Turn left Turn right Turn signal flasher Turn signal switch Exterior Lamps Wiring Diagram, Motorhome Chassis for Chevrolet Forward Control P12 1998 List of elements for Exterior Lamps Wiring Diagram, Motorhome Chassis for Chevrolet Forward Control P12 1998: 54 (7.4l) (forward lamp harn, 5cm from left head- lamp breakout) s102 (forward lamp harn, 5cm from right headlamp breakout) s106 (right rear frame rail) g417 Backup lamps circuit Cruise control system Engine controls system G114 (left rear of engine block) G119 (right front of engine) Hazard Hazard lamps flasher (inner left side of main support bracket) Head Headlamps switch Hot at all times Hot in run I/p fuse block Instrument cluster Interior lamps system Left front park & turn signal (t/s) lamp Left front side marker lamp Left rear license lamp Left rear side marker lamp Left turn indic Nca Normal Off Park Provision for center high mounted stop lamp Provisions for left tail, stop & turn signal (t/s) lamps Provisions for marker lamps Provisions for right tail, stop & turn signal (t/s) lamps Right front park & turn signal (t/s) lamp Right front side marker lamp Right rear license lamp Right rear side marker lamp Right turn indic S105 (forward lamp harn, 9cm from right headlamp breakout) S117 (l19 engine) (engine harness, 43cm from engine cooling fan notor harn breakout) (l29/l65 engine) (engine harness, 7cm from windshield wiper motor breakout) S126 S152 (dash harness, 25cm from headlamp switch connector) S165 S402 (rear lamp harness, rear of vehicle) S404 (rear lamp harness, rear of vehicle) S405 (rear lamp harness, rear of vehicle) S500 Stop haz fuse 11 15a Tail lamps fuse 7 20a Torque converter clutch & stop lamps switch (brake pedal support bracket) Turn Turn b/u fuse 5 15a Turn left Turn right Turn signal flasher Turn signal switch
GROUND DISTRIBUTION Ground Distribution Wiring Diagram, Commercial Chassis (1 of 2) for Chevrolet Forward Control P12 1998 List of elements for Ground Distribution Wiring Diagram, Commercial Chassis (1 of 2) for Chevrolet Forward Control P12 1998: 47 (body builder installed) (forward lamps harn, 4cm after first horn breakout) (i/p harn, 4cm before i/p fuse block breakout) 87a A/c compressor clutch coil A/c compressor refrigerant pressure switch A/c compressor relay A/t shift lock control relay A/t shift lock control solenoid A/t shift lock control solenoid relay Auxilary engine coolant fan motor Battery Braided strap Data link Daytime running lamps control module Daytime running lamps relay Diesel Electronic brake control module Engine block Engine coolant level switch G106 (behind left headlamp) G107 (behind right headlamp) G113 (left frame rail) G113 (left front frame rail) G117 (right rear of engine) G417 (right rear frame rail) Gasoline Glowplug telltale relay (mechanical) I/p convenience center I/p dimmer switch Inline to fuel pump sender Inline to fuel system Left headlamp (w/o drl) Left horn Provisions for left side marker lamp Right headlamp Right horn S103 S110 (engine harn, 4cm from brake pressure differential breakout) S110 (engine harn, near left bulkhead connector) S168 (engine harn, 3.5cm from battery junction block breakout) S205 S401 (rear lamps harn, left rear frame rail) S406 (chassis harn, near breakout to g417) Secondary battery (diesel only) Secondary high pressure switch Starter relay Ground Distribution Wiring Diagram, Commercial Chassis (2 of 2) for Chevrolet Forward Control P12 1998 List of elements for Ground Distribution Wiring Diagram, Commercial Chassis (2 of 2) for Chevrolet Forward Control P12 1998: 40 (a/t) (engine harn, near throttle position sensor) (m/t) 5.7l A/c compressor high pressure cut off switch A/t A/t output speed sensor shield Brake pressure differential switch Data link Diesel Electronic brake control module Electronic ignition control module Firewall) Fuel heater Fuel pump relay Fuel pump relay (diesel) G114 (left rear of engine) G117 (left rear of engine) G119 (right front of engine) Gasoline Glowplug control relay Heated oxygen sensor bank 1 sensor 1 Heated oxygen sensor bank 1 sensor 2 Heated oxygen sensor bank 2 sensor 1 Heated oxygen sensor bank 2 sensor 2 Inline to fuel pump Instrument cluster M/t Mass air flow sensor Powertrain/ vehicle control module S118 (a/t)(engine harn, near glowplug controller breakout) (m/t)(engine harn, near starter motor breakout) S118 (engine harn, left rear of engine) S138 S161 (ebcm harn, 15cm from right wheel speed sensor breakout) S218 (i/p harn, 6cm before i/p fuse block breakout) Starter relay Transmission control module (diesel) Vehicle speed sensor buffer (diesel) Vehicle speed sensor shield Water in fuel indicator sensor Ground Distribution Wiring Diagram, Motor Home Chassis (1 of 2) for Chevrolet Forward Control P12 1998 List of elements for Ground Distribution Wiring Diagram, Motor Home Chassis (1 of 2) for Chevrolet Forward Control P12 1998: 49 (6.5l) (6.5l) (7.4l) (7.4l) (body builder installed) (i/p harn, near right headlamp breakout) 7.4l A/c compressor high pressure cutoff switch A/t output speed sensor shield Battery Braided strap Daytime running lamp relay no 2 Electronic brake control module Engine block Fuel heater Fuel pump relay G111 (near battery) G112 (left side of engine) G113 (left frame rail) G113 (left front frame rail) G115 (near ignition coil) G119 (right front of engine) Glowplug controller Heated oxygen sensor bank 1 sensor 1 Heated oxygen sensor bank 1 sensor 2 Heated oxygen sensor bank 2 sensor 1 Heated oxygen sensor bank 2 sensor 2 Ignition control module Left headlamp Left headlamp inner Left headlamp outer Left horn Mass air flow sensor Park/ neutral position switch relay R100 (near a/c compressor clutch) Right headlamp Right headlamp inner Right headlamp outer Right horn S104 S135 (7.5l) (engine harn, near o2 sensor breakout) (6.5) (eng harn, near glow plug controller breakout) S168 s126 (engine harn, near cruise control module breakout) Secondary battery (diesel only) Starter relay Stop lamp resistor Underhood fuse/relay center W/ dual headlights W/o drl W/o dual headlights Water in fuel indicator sensor Ground Distribution Wiring Diagram, Motor Home Chassis (2 of 2) for Chevrolet Forward Control P12 1998 List of elements for Ground Distribution Wiring Diagram, Motor Home Chassis (2 of 2) for Chevrolet Forward Control P12 1998: 49 6.5l diesel 7.4l 87a A/c compressor clutch coil A/c compressor high pressure cutoff switch A/c compressor refrigerant pressure switch A/t shift lock control solenoid A/t shift lock control solenoid relay Audio alarm Brake pressure differential switch Coolant fan motor Coolant level switch Cruise control module Data link Data link connector Daytime running lamps control module Daytime running lamps relay Electronic brake control module G114 (left rear of engine block) G116 (left side of firewall) G202 (left side of dash) G416 (left rear frame rail) G417 (right rear frame rail) I/p dimmer switch I/p fuse block Iniline to fuel pump and fuel sender (7.4l) inline to fuel sender (6.5l) Inline to fuel pump (6.5l) Inline to steering column harness Instrument cluster Left side marker lamp Park brake position switch Park brake position switch relay Park brake pressure valve solenoid Park brake pump motor Park brake pump relay Pull button park brake relay Pulse wiper control module Right side marker lamp S150 (i/p harn, near fuse panel) S165 (i/p harn, 25cm from breakout to instrument panel) S166 (engine harn, 5cm from breakout to abs harness) S167 (in abs harness) S203 (engine harn, near main wiring pass through at firewall) S203 (i/p harn, 4cm from windshield wiper motor breakout) S212 (i/p harn, 20cm before i/p fuse block breakout) S400 (in rear fuel sender harness) Secondary high pressure switch Vechile control module (7.4l) powertrain control module (6.5l) Vehicle speed sensor buffer
HEADLIGHTS Headlight Wiring Diagram, Commercial Chassis with DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Commercial Chassis with DRL for Chevrolet Forward Control P12 1998: 44 (left rear of engine) g114 Acc Bulb test Daytime running lamps control module (attached to i/p harness at steering column) Daytime running lamps relay (left interior bulkhead, on relay bracket) Diode network (15cm from i/p fuse block breakout) Drl indicator Fog lamps G107 (behind right headlamp) G107 behind right headlamp) Gauges fuse 8 20a Ground Head Headlamp dimmer switch Headlamps switch Hi beam indicator Hi bm feed Hi bm indicator Hot at all times Hot in run or start I/p fuse block Ignition Ignition switch Instrument cluster Lamp feed Left head- lamp Lock Off Park Park brake in Park brake indicator switch (on park brake) Pnk Provision for fog lamps Red Relay out Right head- lamp Run S103 S143 S205 S207 S216 (i/p harn, approx 24cm from i/p fuse block breakout) Start Tan Headlight Wiring Diagram, Commercial Chassis without DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Commercial Chassis without DRL for Chevrolet Forward Control P12 1998: 18 G114 (left rear of engine) Gio7 (behind right headlamp) Head Headlamp Headlamps dimmer switch Headlamps switch Hi beam indicator Hot at all times Instrument cluster Left hi headlamp Off Park Red Right lo S150 S206 S218 Tan Headlight Wiring Diagram, Motor Home Chassis with Dual Headlamps with DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Motor Home Chassis with Dual Headlamps with DRL for Chevrolet Forward Control P12 1998: 51 (body builder installed) (forward lamps harn, 12cm to breakout for left headlamp) s101 (left rear of engine block) g114 (provision for fog lamps) Acc Bulb test Daytime running lamps module (attached to i/p harness at steering column) Daytime running lamps relay (on main support bracket at driver's island) Daytime running lamps relay 2 Diode network Drl indicator Fog lamps G202 (left side of dash) Gauges fuse 20a Ground Head Head- lamp dimmer switch Headlamps switch Hi beam indicator Hi bm feed Hi bm indicator Hot at all times Hot in run or start I/p fuse block Ignition Ignition switch Instrument cluster Instrument cluster system Lamp feed Left head- lamp Left high beam head- lamp Lock Off Park Park brake in Park brake indicator switch (on park brake) Pnk Red Relay out Right head- lamp Right high beam head- lamp Run S104 S150 S151 (i/p harn, 5cm from breakout for headlamp switch) S154 S156 S162 (i/p harn, 70cm from i/p fuse block) S165 Start Tan Headlight Wiring Diagram, Motor Home Chassis with Dual Headlamps without DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Motor Home Chassis with Dual Headlamps without DRL for Chevrolet Forward Control P12 1998: 21 (body builder installed) (forward lamp harn, 12cm to breakout for left headlamp) G114 (left rear of engine block) Head Head- lamp Headlamps dimmer switch Headlamps switch Hi beam indicator Hot at all times Instrument cluster Left hi head- lamp Left high beam head- lamp Off Park Red Right high beam head- lamp Right lo S104 S156 S165 Tan Headlight Wiring Diagram, Motor Home Chassis with Single Headlamps with DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Motor Home Chassis with Single Headlamps with DRL for Chevrolet Forward Control P12 1998: 46 (body builder installed) (left rear of engine) g114 (provision for fog lamps) Acc Bulb test Daytime running lamps module (attached to i/p harness at steering column) Daytime running lamps relay (on main support bracket at driver's island) Diode network Drl indicator Fog lamps G202 (left side of dash) Gauges fuse 20a Ground Head Head- lamp dimmer switch Headlamps switch Hi beam indicator Hi bm feed Hi bm indicator Hot at all times Hot in run or start I/p fuse block Ignition Ignition switch Instrument cluster Instrument cluster system Lamp feed Left head- lamp Lock Off Park Park brake in Park brake indicator switch (on park brake) Pnk Red Relay out Right head- lamp Run S104 S150 S151 (i/p harn, 5cm from breakout for headlamp sw) S154 S162 (i/p harn, 70cm from i/p fuse block) S218 Start Tan Headlight Wiring Diagram, Motor Home Chassis with Single Headlamps without DRL for Chevrolet Forward Control P12 1998 List of elements for Headlight Wiring Diagram, Motor Home Chassis with Single Headlamps without DRL for Chevrolet Forward Control P12 1998: 18 (body builder installed) G114 (left rear of engine block) Head Headlamp Headlamps dimmer switch Headlamps switch Hi beam indicator Hot at all times Instrument cluster Left hi headlamp Off Park Red Right lo S104 S156 S165 Tan
HORN Horn Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Horn Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 18 (1997) s103 (1998) s150 (forward lamp harness, 11 cm from right horn breakout) (left interior bulkhead) (left interior bulkhead) (body builder installed) g202 C 1995 vftc G106 (body builder installed) (left lamps breakout) G107 (body builder installed) (right lamps breakout) Horn relay Horn switch Horn/dm fuse 20a Hot at all times I/p fuse block Left horn (low tone a-note) (body builder installed) Right horn (high tone f-note) (body builder installed) S100 S204 S205 Steering wheel Horn Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Horn Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 18 (body builder installed) (forward lamp harness, 27 cm from left headlamp breakout) (i/p harness, near bulkhead connector) Body builder connector (partial) C 1995 vftc C203 Horn relay (on driver's island) Horn switch Horn/dm fuse 20a Hot at all times I/p fuse block Left horn (body builder installed) Right horn (body builder installed) S100 S104 S153 S204 Steering wheel
INSTRUMENT CLUSTER Instrument Cluster Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Instrument Cluster Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 77 (4.3/5.7l: on left side of engine compt) (7.4l: on center front of engine compt) vehicle control module (abs harn, 11cm from abs ground) (body builder ground) (dash harn, 10cm from i/p fuse block) s214 (dash harn, 24cm from i/p fuse block) s216 (not used) (on power steering gear outlet hose fitting) p/b booster pump pressure switch (on top left rear of engine) (6.5l diesel) engine oil pressure gauge sensor (power steering gear outlet hose fitting) p/b booster fluid flow ind/alarm switch Abs ind Accy Anti-lock brakes system Brake ind Bulb test Check gauges ind Coolant temperature gauge Diesel Diode network (dash harn, 15cm from i/p fuse block) Drl ind Drl module (behind dash, above steering column) Ecm 1 fuse 12 20a Electronic brake control module (ebcm) (below radiator, on first crossmember) Eng 1 fuse 15 20a Engine controls or starting/charging system Engine controls system Engine coolant level switch (on lower left end of radiator surge tank) Engine coolant temperature gauge sensor (4.3l: on left rear side of left cylinder head) (5.7l: on left cylinder head, between two front spark plugs) (6.5l vin f: on left front of engine, behind p/s pump) (6.5l vin y: on left front of left cylinder head) (7.4l: on front center of engine coolant intake) Exterior lights system Fuel gauge Fuel pump switch & engine oil pressure gauge sensor (gasoline) (on engine block, top rear, near distributor) Fuel sender (on top of fuel tank) G114 (left rear of engine) Gas Gauges fuse 8 20a Headlights system Headlights system Hi beam ind Hot in run or start I/p fuse block (body builder installed) Ignition switch Illumination Inline connector fuse block (body builder connection) Instrument cluster Interior lights system Left turn ind Lock Low coolant ind Nca Off Oil pressure gauge P/b booster fluid flow alarm (taped to dash harn at breakout to dash fuse block & headlamps switch) P/b booster fluid flow ind/alarm delay module (taped to dash harn at breakout to dash fuse block & headlamps switch) Park brake indicator switch (body builder installed) Pnk Right turn ind Run S110 S118 S166 S218 S406 Seat belt ind Service engine soon ind Service throttle soon ind Speedometer Start Tachometer Tan Trans ind Transmissions system Voltmeter W/ drl W/o drl Wait to start ind Warning systems Water in fuel ind Water-in fuel sensor (part of fuel/ water seperater (filter), rear of intake manifold) Instrument Cluster Wiring Diagram, Motor Home Chassis (1 of 2) for Chevrolet Forward Control P12 1998 List of elements for Instrument Cluster Wiring Diagram, Motor Home Chassis (1 of 2) for Chevrolet Forward Control P12 1998: 60 (body builder ground) (on center front of engine compt) vehicle control module (on top left rear of engine) (6.5l diesel) engine oil pressure gauge sensor Abs ind Accy Anti-lock brakes system Auto park ind Brake ind Bulb test Check gauges ind Coolant temperature gauge Diesel Drl ind Ecm 1 fuse 12 20a Eng 1 fuse 15 20a Engine controls or starting/ charging system Engine controls system Engine coolant level switch (on lower left end of radiator surge tank) Engine coolant temperature gauge sensor (6.5l: on left front of engine) (7.4l: on front of engine coolant intake) Exterior lights system Fuel gauge Fuel pump switch & engine oil pressure gauge sensor (7.4l gas) (on engine block, top rear, behind distributor) Fuel sender (on top of fuel tank) G114 (left rear of engine block) G133 (on engine) Gas Gauges fuse 8 20a Headlights system Headlights system Hi beam ind Hot in run or start I/p fuse block (body builder installed) Ignition switch Illumination Instrument cluster Interior lights system Left turn ind Lock Low coolant ind Off Oil pressure gauge Pnk Right turn ind Run S135 S165 S203 S400 Seat belt ind Service engine soon ind Service throttle soon ind Speedometer Start Tachometer Tan Voltmeter Wait to start ind Warning systems Water in fuel ind Water-in fuel sensor (part of fuel/ water seperater (filter), rear of intake manifold) Instrument Cluster Wiring Diagram, Motor Home Chassis (2 of 2) for Chevrolet Forward Control P12 1998 List of elements for Instrument Cluster Wiring Diagram, Motor Home Chassis (2 of 2) for Chevrolet Forward Control P12 1998: 48 (abs harn, 11cm from abs ground) s166 (body builder connector) (body builder ground) (dash harn, 18cm from headlamp switch breakout) s162 (not used) 87a Accy Bulb test Diode d300 Diode d301 Diode network (dash harn, 15cm from i/p fuse block) Drl module (behind dash, above steering column) Electronic brake control module (ebcm) (below radiator, on first crossmember) G115 (near ignition coil) Hot at all times Hot in run or start I/p fuse block (body builder installed) Ignition switch Lock Nca Off Park brake actuator position switch Park brake actuator position switch relay Park brake alarm Park brake indicator switch (body builder installed) Park brake pressure indicator switch (on right frame rail, behind trans) Park brake pressure valve solenoid Park brake pump motor (on right frame rail, behind trans) Park brake pump motor relay (on right frame rail, behind trans) Park brake pump motor switch (on right frame rail, behind trans) Park/neutral position switch relay Pnk Pull button park brake switch Pull button relay (on left side of driver's island) Red Run S135 S149 (dash harn, near dash fuse block) S150 S168 S169 S205 (dash harn, 76cm from fuse block) S363 S364 Shift interlock system Start W/ drl W/o drl
INTERIOR LIGHTS Interior Light Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Interior Light Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 31 (5) Breakout) C207 Dash lamps input Dim Dome lamp switch Exterior lights system G107 (behind right headlamp) G114 (left rear of engine) Head Headlamps switch High Horn dim fuse 20a Hot at all times I/p fuse block I/p lamps dimmer switch Instr lps fuse 16 5a Instrument cluster Light switch Off Panel lamps switch Park Prndl lamp Provision for dome lamp Provision for marker lamps S168 S204 S205 S218 Seat belt alarm (bottom of i/p fuse block) Tail lps fuse 7 20a Interior Light Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Interior Light Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 31 (5) (i/p harn, 25 cm from head- lamp switch conn) (left side of dash) Dim Dome lamp switch Exterior lights system G114 (left rear of engine block) G202 Head Headlamps switch High Horn dm fuse 3 20a Hot at all times I/p fuse block I/p lamps dimmer switch Instr lps fuse 16 5a Instrument cluster Lamp Light switch Off Panel lamps switch Park Prndl lamp Provision for dome b Provision for roof marker lamps S150 S152 S153 S165 Seat belt alarm (bottom of i/p fuse block) Tail lps fuse 7 20a
POWER DISTRIBUTION Power Distribution Wiring Diagram, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Commercial Chassis (1 of 4) for Chevrolet Forward Control P12 1998: 51 (105a) (diesel a/t-engine harness, approx 19 cm from a/c compresssor clutch relay, others-engine harness, approx 11 cm from steering column connector breakout) s144 (diesel-engine harness, 4-16 cm from starter motor breakout, gasoline-engine harness, 7 cm from generator jumper breakout) s112 (i/p harness, approx 20 cm from fuse block breakout) s204 (others) A/c compressor clutch relay A12 Accessory junction block (left interior bulkhead, near relay bracket) Auxiliary engine coolant fan relay (diesel only) Batt bus Battery Battery junction block (left side of engine bulkhead) C13 D13 Data link connector Diesel Dome lamp (provisions for) Ecm- bat fuse 6 20a Electronic brake control module Eng- bat fuse 10 15a Engine pressure indicator sensor Fuel pump relay Fusible link (18 ga. rust) Fusible link 10 ga. rust Gas Generator Glow plug control module (diesel) Hazard lamp flasher Headlamps switch Horn relay Horn/ dm fuse 3 20a I/p fuse block (dash panel provided by body builder) Powertrain control module Pwr bus Pwr circuit breaker 30a Red Remote battery access terminal block (rear of right radiator core support panel) S134 S206 (i/p harness, approx 12 cm before dash fuse block breakout) Seat belt/ lamps alarm module Secondary battery (diesel only) Starter relay Starter solenoid Stop- haz fuse 11 15a Stud Tail lps fuse 7 20a To ignition switch (diagram 2 of 4) Torque converter clutch & stoplamps switch Transmission control module (a/t only) Vehicle control module W/deluxe school bus option Power Distribution Wiring Diagram, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Commercial Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 54 (elec) (engine harness, approx 18 cm from right engine breakout) (engine harness, approx 5 cm from right glowplug breakout) s116 (engine harness, approx 6 cm before mass air flow sensor breakout) s116 (i/p harness, approx 15 cm after i/p fuse block breakout) s211 (mech) A a6 A b6 A c6 A d6 A/t Acc Acc bus Acc radio fuse 4 10a Automatic transmission Auxiliary engine coolant fan relay Camshaft position sensor (4.3l) Camshaft position sensor (5.7l) Canister vent sensor (4.3l) Canister vent sensor (5.7l) Clutch pedal position switch Cold advance solenoid and engine coolant temperature switch Crank fuse 10a Crk (start) Diesel Eng-1 fuse 15 20a Evaporative emissions canister purge valve solenoid From fusible link (diagram 1 of 4) Fuel heater Gas Glow plug control switch I/p fuse block (dash panel provided by body builder) Ignition switch In-line fuse block (near right side of steering column) Left post oxygen sensor (5.7l/ 4.3l Left pre- heated oxygen sensor (4.3l/ 5.7l) Lock M/t Mass air flow sensor (4.3l/ 5.7l) Off On (run) Park/neutral position and backup lamps switch Pnk Provisions for windshield washer motor Red Right post oxygen sensor (5.7l) Right pre- heated oxygen sensor (4.3l/ 5.7l) S139 To ecm-1 fuse (diagram 3 of 4 and diagram 4 of 4) To i/p fuse block: (diagram 4 of 4) Trans fuse 17 10a Water- in-fuel indicator sensor Windshield wiper & washer switch Wiper fuse 14 25a Power Distribution Wiring Diagram, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Commercial Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 15 (engine harness, 9cm from breakout to right oxygen sensor) s108 (engine harness, approx 10 cm from breakout to right side of engine crossover harness) s108 4.3l vin w 5.7l vin r Crankshaft position sensor Ecm-1 fuse 12 20a Electronic ignition control module From eng-1 fuse (diagram 2 of 4) Fuel injector I/p fuse block (dash panel provided by body builder) Ignition coil Instrument cluster Pnk S145 Vehicle control module Power Distribution Wiring Diagram, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Commercial Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 57 (engine harness, 8cm from vcm breakout) s133 (engine harness, approx 19 cm pnk (engine harness, approx 26 cm from bulkhead grommet) (i/p harness, approx 40 cm before i/p fuse block breakout) 105a 1996 vftc c 6.5l engine A/c compressor clutch relay A/t Aux circuit breaker 13 30a Aux fuse 30a Back up lamps switch C11 C12 C16 Daytime running lamp relay Daytime running lamps control module Diesel Ecm-1 fuse 12 20a Electronic brake control module Engine controls From breakout to steering column connector) s132 From eng 1 fuse (diagram 2 of 4) From ignition switch (diagram 2 of 4) Fuel injection pump fuel shut-off solenoid Fuel injection pump shut-off solenoid Fuel pump relay (mech) Gas Gauges fuse 8 20a Generator Htr bus Htr fuse 1 25a I a4 I b4 I c4 I-3 fuse 9 15a I/p fuse block (dash panel provided by body builder) Ign bus Instrument cluster Instrument lamps fuse 5a Interior lights system Interior lights system (i/p lamps dimmer switch) M/t Others Park/ neutral position and backup lamps switch Pnk Powertrain control module (elec) S108 S207 Seat belts lamp alarm module Torque converter clutch & stop lamps switch Transmission control module (a/t) Turn signal flasher Turn- b/u fuse 5 15a Vehicle control module (vcm) Vehicle speed sensor (a/t) Vehicle speed sensor (vss) buffer Power Distribution Wiring Diagram, Motor Home Chassis (1 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Motor Home Chassis (1 of 4) for Chevrolet Forward Control P12 1998: 51 (6.5l) (7.4l) (7.4l vin j-engine harness, 44 cm from breakout for left wheel speed sensor, 6.5l-engine harness, 20 cm from breakout of main harness) (i/p harn, 15cm from bulkhead connector) (i/p harness, 6 cm from breakout for headlamp switch) 6.5l vin f 7.4l 7.4l vin j A/c compressor relay Alternator Auxiliary fan control relay Battery Battery junction block (on forward left side of the bulkhead) Buss bar C d C13 D13 Data link connector Diesel Dome lamp Ecm- bat fuse 6 20a Electronic brake control module Eng- bat fuse 10 15a Fan control relay Fuel pump relay Fuel pump switch and oil pressure gauge Fusible link (10 ga. red) Fusible link (10 ga. rust) Glow plug controller Hazard flasher Headlamps switch Horn relay Horn/ dm fuse 3 20a I/p fuse block (mounted on the dash) Ignition switch (diagram 2 of 4) Powertrain control module Pwr circuit breaker 30a Red Red a S114 S125 (7.4l-engine harness 5 cm from breakout for egr 6.5l-engine harness, 9 cm from breakout for generator) S141 S153 S156 (i/p harness, 35 cm from fuse panel) Seatbelts/ lamps alarm module Secondary battery (diesel only) Starter motor Starter relay Stop- haz lps fuse 11 15a Stoplamp switch Tail lamps fuse 7 20a Vehicle control module Power Distribution Wiring Diagram, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Motor Home Chassis (2 of 4) for Chevrolet Forward Control P12 1998: 56 (7.4l-eng harn, 58cm from main passthrough 6.5l-eng harn, 7.5cm from a/c harn breakout) (i/p harn, 25cm from fuse panel) s157 (i/p harn, 25cm from instrument cluster breakout) (i/p harn, 54cm from fuse block) (i/p harn, 70cm from i/p fuse block) s162 6.5l vin f 7.4l vin j Acc Acc radio fuse 4 10a Automatic transmission Auxiliary fan control relay Camshaft position sensor Crank fuse 18 10a Daytime running lamp control module Diesel Diode network Eng-1 fuse 20a Engine coolant level switch Engine harness, 10 cm from breakout for ignition coil) s133 Engine harness, 12cm from breakout for glow plug control) s128 Evaporative emissions canister purge valve solenoid From fusible link (diagram 1 of 4) Fuel heater Glow plug control Heated oxygen sensor bank 1 sensor 1 Heated oxygen sensor bank 1 sensor 2 Heated oxygen sensor bank 2 sensor 1 Heated oxygen sensor bank 2 sensor 2 I/p fuse block (mounted on the dash) Ignition switch Instrument cluster Lock Mass air flow sensor Nca Off Park brake actuator position switch relay Park brake alarm Park brake switch Park low pressure switch Park/neutral position and backup lamps switch Pnk Pnk a Pnk a1 Pull button park brake switch Pull button relay Red Run S161 (i/p harn, 18cm from fuse panel) S165 Start To aux fuse (diagram 4 of 4) To gauges fuse (diagram 4 of 4) Trans fuse 17 10a Water in-fuel indicator sensor Wiper fuse 14 25a Wiper motor Power Distribution Wiring Diagram, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Motor Home Chassis (3 of 4) for Chevrolet Forward Control P12 1998: 22 (engine harness, 28 cm from breakout for injectors) (fuel injector harness, 7 cm from breakout for injector 5) s158 (fuel injector harness, 7 cm from breakout for injector 5) s159 6.5l vin f 6.5l-engine harness, 16cm from bulkhead grommet) s121 7.4l vin j C11 C12 Crankshaft position sensor Ecm-1 fuse 20a Electronic ignition control module Engine shut-off solenoid From gauges fuse diagram 4 of 4) I/p fuse block (mounted on the dash) Ignition coil Injector Instrument cluster Pnk Powertrain control module S121 Vehicle control module Vehicle speed sensor calibrator Power Distribution Wiring Diagram, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998 List of elements for Power Distribution Wiring Diagram, Motor Home Chassis (4 of 4) for Chevrolet Forward Control P12 1998: 38 (7.4l-engine harness, 52 cm from breakout for map sensor, 6.5l-engine harness, 33 cm from breakout for windshield wiper switch) s116 (engine harness, 34cm from windshield wiper motor breakout) s115 (i/p harness, 12 cm from breakout for headlamp switch) s154 1996 vftc c 6.5l vin f engine only 7.4l vin j engine 7.4l vin j engines A/c compressor relay Alternator Aux circuit breaker 30a Body builder circuit breaker Buss bar Canadian models Cruise control module Cruise control switch Daytime running lamps control module Daytime running lamps control relay Electronic brake control module From eng-1 fuse d (diagram 2 of 4) From ignition switch (diagram 2 of 4) Gauges fuse 8 20a Htr fuse 1 25a I-3 fuse 9 15a I/p fuse block (mounted on the dash) Instr- lps fuse 16 5a Instrument cluster Interior lights system Interior lights system (instrument panel dimmer switch) Park/neutral position & backup switch Pnk Seatbelts/ lamps alarm module Steering column harness Stoplamp torque converter clutch switch To ecm 1 fuse diagram 3 of 4) Turbo charger power valve solenoid Turn b/u fuse 5 15a Turn signal flasher Vehicle control module
SHIFT INTERLOCKS Shift Interlock Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Shift Interlock Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 21 Body builder installed Brake Brake/transmission shift interlock (btsi) relay (top of support bracket, at driver's island) Brake/transmission shift interlock (btsi) solenoid (on steering column) Diesel Electronic brake control module (below radiator on crossmember) Gasoline Hot in run I-3 fuse 15a I/p fuse block Ign Park/neutral position and backup lamps switch (left of trans) S110 S133 S168 (diesel only) S200 (dash side of eng harn, approx 17 cm from grommet left of bulkhead conn) Torque converter clutch and stop lamps switch (right side of steering column) Trans- mission control module (tcm) (left interior firewall) Turn b/u fuse 15a Turn signal flasher (on fuse block) Vehicle control module (vcm) (left side of eng compt) Shift Interlock Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Shift Interlock Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 24 (on crossmember, front of vehicle) electronic brake control module (on fuse block) turn signal flasher (rear of brake support bracket) Brake Brake/transmission shift interlock (btsi) relay (top of support bracket at driver's island)) Brake/transmission shift interlock (btsi) solenoid (on steering column) Cruise control module Diesel G202 (left side of i/p) Gasoline Hot in run I-3 fuse 15a I/p fuse block Ign Park/ neutral position switch relay Park/neutral position & backup lamp switch (left of trans) Power- train control module (left of driver's island) S116 S200 (i/p harn, 22 cm from grommet under i/p, toward steering column harn) S203 S210 Torque converter clutch & stop lamps switch Turn b/u fuse 15a Vehicle control module (top of radiator support)
STARTING/CHARGING Charging Wiring Diagram for Chevrolet Forward Control P12 1998 List of elements for Charging Wiring Diagram for Chevrolet Forward Control P12 1998: 22 (124a) (145a) (commercial) s112 (motor home) s125 (commercial-right rear of engine, motor home-near battery) (gasoline) (diesel) (motor home) (commercial) Bat Battery Fusible link (10 ga-rust) G117 (commercial) g111 (motor home) Gauges fuse 8 20a Generator Hot in run and start I/p fuse block Instrument cluster tach (diesel) P10 c Pnk Pnk c f Power distribution system Red S207 (commercial) s154 (motor home) Secondary battery (diesel) Starter solenoid Starting Wiring Diagram for Chevrolet Forward Control P12 1998 List of elements for Starting Wiring Diagram for Chevrolet Forward Control P12 1998: 37 (body builder installed) (commercial) (commercial-rear of right cylinder head, motor home-near battery) (diesel only) (engine harness, approx 33 cm from bulkhead grommet) (motor home) 10a A/t Accy Battery Battery junction block Clutch pedal position switch (top of clutch pedal support) Engine controls system (commercial diesel only) Fusible link (10 ga-rust) G c1 G111 G117 Hold- in coil Ignition switch In line crank fuse 18 (commercial) or i/p fuse block, crank fuse 18 (motor home) Lock M/t Off P or n Park/neutral position and backup lamps switch (left side of transmission) Pull- in coil Red Red b Run S109 S110 (commercial diesel) s118 (commercial gasoline) s135 (motor home) S112 (commercial) s125 (motor home) Secondary battery (diesel) Start Starter motor Starter relay (relay center- gasoline, fuse/ relay center- vin f, under battery junction block-vin y) Starter solenoid
TRANSMISSION
4.3L 4.3L (VIN W), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998 List of elements for 4.3L (VIN W), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998: 75 (a/t output speed sensor) (mil) (twisted wire pair) 1-2 shift 1-2 shift sol 2-3 shift sol 2-3 shift solenoid 5v reference A/c compressor relay, generator & seat belt/ headlamps alarm module A/t input speed sensor (left side of transmission) A/t iss hi in A/t iss lo in Anti-lock brakes, cruise control & shift interlock systems Automatic transmission (4l80-e) Battery in Brake switch input Buss bar Data class ii Data link connector (partial) (below dash, near steering column) Ecm bat fuse 6 20a Ecm-1 fuse 12 20a Ect sens input Electronic brake control module & cruise control module Engine controls system Engine coolant temperture sensor (top front of engine) Fuel injectors (engine controls system) Fuel pump relay & switch G114 (rear of left clinder head) Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ignition in Instrument cluster 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 S108 s121 S118 S118 (7.4l) (eng harn, 19 cm from breakout for left front wheel sensor) S119 (engine harness, near ect sensor- 4.3l/5.7l) (engine harness, 4 cm from generator breakout- 7.4l) S133 s116 S134 s114 S135 S135 (4.3l/5.7l) (eng harn, 8 cm from ect breakout) S143/s166 S150/s202 (i/p harn) S200 (eng harn, 19 cm from firewall grommet towards ignition switch-4.3l/5.7l) (eng harn, 45 cm from map sensor breakout-7.4l) S207 s154 Sensor ground Sensor return Service engine soon indicator Solenoid Tcc pwm Tcc pwm sol Tcc/ stop lamps switch Throttle position sensor (on throttle body) Tp sens input Trans fluid temp sensor Trans fuse 17 10a Trans range pressure switch assembly Trans temp sig in Vehicle control module (center front of engine compt) Vehicle speed sensor (left rear of transmission) Vss hi Vss lo
5.7L 5.7L (VIN R), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998 List of elements for 5.7L (VIN R), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998: 75 (a/t output speed sensor) (mil) (twisted wire pair) 1-2 shift 1-2 shift sol 2-3 shift sol 2-3 shift solenoid 5v reference A/c compressor relay, generator & seat belt/ headlamps alarm module A/t input speed sensor (left side of transmission) A/t iss hi in A/t iss lo in Anti-lock brakes, cruise control & shift interlock systems Automatic transmission (4l80-e) Battery in Brake switch input Buss bar Data class ii Data link connector (partial) (below dash, near steering column) Ecm bat fuse 6 20a Ecm-1 fuse 12 20a Ect sens input Electronic brake control module & cruise control module Engine controls system Engine coolant temperture sensor (top front of engine) Fuel injectors (engine controls system) Fuel pump relay & switch G114 (rear of left clinder head) Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ignition in Instrument cluster 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 S108 s121 S118 S118 (7.4l) (eng harn, 19 cm from breakout for left front wheel sensor) S119 (engine harness, near ect sensor- 4.3l/5.7l) (engine harness, 4 cm from generator breakout- 7.4l) S133 s116 S134 s114 S135 S135 (4.3l/5.7l) (eng harn, 8 cm from ect breakout) S143/s166 S150/s202 (i/p harn) S200 (eng harn, 19 cm from firewall grommet towards ignition switch-4.3l/5.7l) (eng harn, 45 cm from map sensor breakout-7.4l) S207 s154 Sensor ground Sensor return Service engine soon indicator Solenoid Tcc pwm Tcc pwm sol Tcc/ stop lamps switch Throttle position sensor (on throttle body) Tp sens input Trans fluid temp sensor Trans fuse 17 10a Trans range pressure switch assembly Trans temp sig in Vehicle control module (center front of engine compt) Vehicle speed sensor (left rear of transmission) Vss hi Vss lo
6.5L 6.5L (VIN F), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN F), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998: 90 (rear lamps provision connector) (twisted wire pair) 1-2 shift 1-2 shift sol 2-3 shift sol 2-3 shift solenoid 3-2 shift 3-2 shift sol A/c pnk A/t input speed sensor (left side of transmission) A/t iss sens hi in A/t iss sens lo in A12 Accelerator pedal position module (attached to 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 (4l80-e) B10 B12 Battery in Brake switch in Buss bar C11 C12 C13 C14 C15 Class ii data Compressor relay, generator & turbo charger power valve D11 D12 D13 Data link connector (partial) (below dash, near steering column) Ecm-1 fuse 12 20a Ecm-bat fuse 6 20a Ect sensor in Electronic brake control module Engine coolant temperature sensor (top front of engine) Fuel pump relay & fuel pump switch/engine oil pressure indicator sensor G114 (left rear of engine block) Gauges fuse 8 20a Hazard lamps flasher (above steering column) Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ignition in Indicator Instrument cluster Mil control Pcm ground Pcs sol hi out Pcs sol lo out Pnk Powertrain control module (left side of driver's island) Press ctrl solenoid Red S114 S119 (engine harn, 4 cm from glow plug controller break-out) S121 S124 (engine harn, 13 cm from a/c compressor hi-press cut-off switch breakout) S133 S154 S166 S200 (eng harn, dash side near ignition switch) S202 (dash harness) Sensor ground Service engine soon (mil) Solenoid Stop-haz fuse 11 15a Stoplamp switch in Tft sensor in Torque converter clutch brake & stoplamp switch Trans fluid temp sensor Trans range "a" Trans range "b" Trans range "c" Trans range pressure switch assembly Transmission fuse 17 10a Vehicle speed sensor (left rear of transmission) Vehicle speed sensor calibrator & engine shutoff solenoid Vehicle speed sensor calibrator (above accelerator pedal) Vss hi in Vss lo in Vss out 6.5L (VIN Y), Transmission Wiring Diagram, with Electronic Engine Controls for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Transmission Wiring Diagram, with Electronic Engine Controls for Chevrolet Forward Control P12 1998: 89 (rear lamps provision connector) (twisted wire pair) 1-2 shift 1-2 shift sol 2-3 shift sol 2-3 shift solenoid 3-2 shift 3-2 shift sol A/c compressor relay & generator A/t input speed sensor (left side of transmission) A/t iss sens hi in A/t iss sens lo in A12 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 (4l80-e) B10 B12 Battery in Brake switch in Buss bar C11 C12 C13 C14 C15 Class ii data D11 D12 D13 Data link connector (partial) (below dash, near steering column) Ecm-1 fuse 12 20a Ecm-bat fuse 6 20a Ect sensor in Electronic accelerator pedal control (accelerator pedal position module) (attached to accelerator pedal) Electronic brake control module Engine coolant temperature sensor (top front of engine) Fuel pump relay & engine oil pressure indicator sensor G114 (rear of left cylinder head) Gauges fuse 8 20a Hazard lamps flasher (above steering column) Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ignition in Indicator Instrument cluster Mil control Pcm ground Pcs sol hi out Pcs sol lo out Pnk Powertrain control module (left side of driver's island) Press ctrl solenoid Red S108 S119 (engine harn, 4 cm from glow plug controller break-out) S124 (engine harn, 13 cm from a/c compressor hi-press cut-off switch breakout) S133 S143 S150 (dash harness) S170 S200 (eng harn, dash side near ignition switch) S207 Sensor ground Service engine soon (mil) Solenoid Stop-haz fuse 11 15a Stoplamp switch in Tft sensor in Torque converter clutch & stoplamp switch Trans fluid temp sensor Trans range "a" Trans range "b" Trans range "c" Trans range pressure switch assembly Transmission fuse 17 10a Vehicle speed sensor (left rear of transmission) Vehicle speed sensor buffer Vehicle speed sensor buffer (above accelerator pedal) Vss hi in Vss lo in Vss out 6.5L (VIN Y), Transmission Wiring Diagram, without Electronic Engine Controls for Chevrolet Forward Control P12 1998 List of elements for 6.5L (VIN Y), Transmission Wiring Diagram, without Electronic Engine Controls for Chevrolet Forward Control P12 1998: 95 1-2 shift sol 1-2 shift sol ctrl 2-3 shift sol 2-3 shift sol ctrl 5 volts ref 5v in 5v rtn A/t input speed sensor (left front side of transmission) A10 A11 A12 Automatic transmission (4l80-e) B10 B11 B12 Baro sensor input Barometric pressure sensor (top left rear of intake manifold) Battery feed Brake signal C10 C11 C12 C13 C14 C15 C16 D10 D11 D12 D13 D14 D15 D16 Data link connector (partial) (below dash, near steering column) Diagnostic test Drl module, drl relay & generator Ecm-1 fuse 12 20a Ecm-bat fuse 6 20a Electronic brake control module Engine oil pressure indicator sensor & fuel pump relay Engine speed sensor (in fuel injection pump) Engine speed signal Fuel injection pump shutoff solenoid, & fuel pump relay G114 (rear of left cylinder head) Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ign buss Ignition Input speed sens hi Input speed sens lo Instrument cluster Out Pcs hi Pcs lo Pnk Pnk n Pressure control solenoid Range mode selector Range signal a Range signal b Range signal c Red Red p S108 S111 (engine harn, 10 cm from generator breakout) S119 (engine harn, 6 cm from glow plug switch breakout) S133 S143 S170 S200 (engine harn, dash side near ignition switch) S207 Sensor ground Serial data Service trans output Service transmission indicator Stop lamps & torque converter brake switch System ground Tan Tcc pwm control Tcc pwm sol Throttle position sensor (on fuel injection pump) Tp sensor input Trans fluid temp sig Trans fuse 17 10a Transmission control module (left interior firewall) Transmission temperature sensor Vehicle spd output Vehicle speed input Vehicle speed sensor (left rear of transmission) Vehicle speed sensor buffer Vss inputs
7.4L 7.4L (VIN J), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998 List of elements for 7.4L (VIN J), Transmission Wiring Diagram, 4L80-E for Chevrolet Forward Control P12 1998: 75 (a/t output speed sensor) (mil) (twisted wire pair) 1-2 shift 1-2 shift sol 2-3 shift sol 2-3 shift solenoid 5v reference A/c compressor relay, generator & seat belt/ headlamps alarm module A/t input speed sensor (left side of transmission) A/t iss hi in A/t iss lo in Anti-lock brakes, cruise control & shift interlock systems Automatic transmission (4l80-e) Battery in Brake switch input Buss bar Data class ii Data link connector (partial) (below dash, near steering column) Ecm bat fuse 6 20a Ecm-1 fuse 12 20a Ect sens input Electronic brake control module & cruise control module Engine controls system Engine coolant temperture sensor (top front of engine) Fuel injectors (engine controls system) Fuel pump relay & switch G114 (rear of left clinder head) Gauges fuse 8 20a Hot at all times Hot in run Hot in run or start I-3 fuse 9 15a I/p fuse block Ignition in Instrument cluster 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 S108 s121 S118 S118 (7.4l) (eng harn, 19 cm from breakout for left front wheel sensor) S119 (engine harness, near ect sensor- 4.3l/5.7l) (engine harness, 4 cm from generator breakout- 7.4l) S133 s116 S134 s114 S135 S135 (4.3l/5.7l) (eng harn, 8 cm from ect breakout) S143/s166 S150/s202 (i/p harn) S200 (eng harn, 19 cm from firewall grommet towards ignition switch-4.3l/5.7l) (eng harn, 45 cm from map sensor breakout-7.4l) S207 s154 Sensor ground Sensor return Service engine soon indicator Solenoid Tcc pwm Tcc pwm sol Tcc/ stop lamps switch Throttle position sensor (on throttle body) Tp sens input Trans fluid temp sensor Trans fuse 17 10a Trans range pressure switch assembly Trans temp sig in Vehicle control module (center front of engine compt) Vehicle speed sensor (left rear of transmission) Vss hi Vss lo
WARNING SYSTEMS Warning System Wiring Diagrams, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Warning System Wiring Diagrams, Commercial Chassis for Chevrolet Forward Control P12 1998: 22 G106 (behind left Gauges fuse 8 20a Ground Headlamp) Horn/dm fuse 3 20a Hot at all times Hot in run and start Hot w/ park or headlamps switch on I/p fuse block Instr lps fuse 16 5a Instrument cluster Lamp on input Pnk Power (battery) Power (ignition) S204 S205 S207 S209 Seat belt input Seat belt lamp output Seat belt/lamps alarm (at the bottom of the i/p fuse block) Warning System Wiring Diagrams, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Warning System Wiring Diagrams, Motor Home Chassis for Chevrolet Forward Control P12 1998: 22 G202 (left side of dash) Gauges fuse 8 20a Ground Headlamps switch on Horn/dm fuse 3 20a Hot at all times Hot in run and start Hot w/ park or I/p fuse block Instr lps fuse 16 5a Instrument cluster Lamp on input Pnk Power (battery) Power (ignition) S150 S153 S154 S155 Seatbelt switch Seatbelt tell tale Seatbelt/lamps alarm module (at the bottom of the i/p fuse block)
WIPER/WASHER Provisions For Front Wiper/Washer Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998 List of elements for Provisions For Front Wiper/Washer Wiring Diagram, Commercial Chassis for Chevrolet Forward Control P12 1998: 13 (1996-97) (1998-99) (first breakout from bulkhead connector) High Hot in accy or run I/p fuse block Low Mist Off Pnk Provisions for wiper/washer motor Wash Windshield wiper and washer switch Wiper fuse wiper fuse 14 25a Provisions For Front Wiper/Washer Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998 List of elements for Provisions For Front Wiper/Washer Wiring Diagram, Motor Home Chassis for Chevrolet Forward Control P12 1998: 20 (1996-97,1999) s150 (1998) s203 (1998-99) g202 (left side of dash) 1996-97 1998/ Delay rheo- stat G202 (1996-97) (on driver's island) High Hot in accy and run I/p fuse block Low Mist Off Pnk Provisions for wiper/washer motor Pulse Pulse wiper control module (strapped to harness under driver's island) Wash Wiper fuse 14 25a Wiper fuse 25a Wiper/ washer switch
