Chevrolet Forward Control P30 1990 - ELECTRICAL COMPONENT LOCATOR 1989-90 ELECTRICAL COMPONENT LOCATIONS General Motors Corp. - Electrical Components

Chevrolet Forward Control P30 1990 - BUZZERS, RELAYS & TIMERS

Chevrolet Forward Control P30 1990 BUZZERS, RELAYS & TIMERS LOCATION

Component	Location
A/C-Heater Blower Relay	On evaporator case, in engine compartment.
Auxiliary Cooling Fan Relay	On right side of firewall. See Fig. 1.
Cold Advance Control Relay (Diesel)	On right side of firewall.
Downshift Relay 3L80 (THM 400)
Component View	On right side of firewall. See Fig. 1.
4.3L	On right side of firewall. See Fig. 2.
5.0L & 5.7L - 1989	On right side of firewall. See Fig. 3.
5.0L & 5.7L - 1990	On right side of firewall. See Fig. 4.
7.4L - 1989	On right side of firewall. See Fig. 5.
7.4L - 1990	On right side of firewall. See Fig. 6.
Fuel Pump Relay
Component View	On right side of firewall. See Fig. 1.
4.3L	On right side of firewall. See Fig. 2.
5.0L & 5.7L - 1989	On right side of firewall. See Fig. 3.
5.0L & 5.7L - 1990	On right side of firewall. See Fig. 4.
7.4L - 1989	On right side of firewall. See Fig. 5.
7.4L - 1990	On right side of firewall. See Fig. 6.
Hazard Flasher Relay	Under left side of dash.
Horn Relay	Behind left side of dash, on harness near fuse block.
Power Door Lock Delay Relay	Behind left side of dash, above kick panel.
Power Door Lock Relay	Behind left side of dash, above kick panel.
Turn Signal Flasher Relay	On fuse block.

Chevrolet Forward Control P30 1990 - CIRCUIT PROTECTION DEVICES

Chevrolet Forward Control P30 1990 CIRCUIT PROTECTION DEVICES LOCATION

Component	Location
Battery Junction Block (1989 ONLY)	On left side of firewall.
Circuit Breakers
Headlight/Parking Light	In headlight switch.
Power Door Lock	On fuse block.
Power Window	On fuse block.
Rear A/C	On firewall.
Convenience Center	Under left side of dash.
Fuse Block
4.3L	Under left side of dash. See Fig. 2.
5.0L & 5.7L - 1989	Under left side of dash. See Fig. 3.
5.0L & 5.7L - 1990	Under left side of dash. See Fig. 4.
7.4L - 1989	Under left side of dash. See Fig. 5.
7.4L - 1990	Under left side of dash. See Fig. 6.
Fusible Links
A/C-Heater (Red)	At battery junction block (rear unit).
Alternator (Rust)	At battery junction block.
Auxiliary Cooling Fan Relay (Rust)	At battery junction block.
Glow Plug Controller (Rust) (Diesel)	At starter solenoid.
Ignition Switch (Rust)	At battery junction block (2 links).
Power Accessories (Rust)	At battery junction block.

Chevrolet Forward Control P30 1990 - CONTROL UNITS

Chevrolet Forward Control P30 1990 CONTROL UNITS LOCATION

Component	Location
Audio Alarm Module	On bracket, to left of steering column.
Cruise Control Module	On brake pedal bracket.
Electronic Control Module (ECM)
4.3L	Under driver's seat. See Fig. 2.
5.0L & 5.7L - 1989	Under driver's seat. See Fig. 3.
5.0L & 5.7L - 1990	Under driver's seat. See Fig. 4.
7.4L - 1989	Under driver's seat. See Fig. 5.
7.4L - 1990	Under driver's seat. See Fig. 6.
Elect. Spark Control (ESC) Module
4.3L	Under driver's seat. See Fig. 2.
5.0L & 5.7L - 1989	Under driver's seat. See Fig. 3.
5.0L & 5.7L - 1990	Under driver's seat. See Fig. 4.
Glow Plug Controller (Diesel)
Diesel Component View	On left rear of intake manifold. See Fig. 7.
Diesel Engine Component View	On left rear of intake manifold. See Fig. 8.
Hot Fuel Handling Module
5.0L & 5.7L - 1989	Under driver's seat. See Fig. 3.
5.0L & 5.7L - 1990	Under driver's seat. See Fig. 4.
7.4L - 1989	Under driver's seat. See Fig. 5.
7.4L - 1990	Under driver's seat. See Fig. 6.
Hydro-Boost Elect. Delay Module	Behind left side of instrument panel.
Light Driver Module (Diesel)	Under right side of dash.
Power Door Lock Delay Module	Above left kick panel.
Pulse Wiper Control Module	Taped to harness, at right side of steering column.
RWAL Elect. Control Unit	In engine compartment on bracket attached to master cylinder.

Chevrolet Forward Control P30 1990 - SENDING UNITS & SENSORS

Chevrolet Forward Control P30 1990 SENDING UNITS & SENSORS LOCATION

Component	Location
Coolant Level Sensor	In radiator.
Coolant Temp. Sending Unit/Switch	On left cylinder head. See Fig. 8.
Coolant Temperature Sensor
Diesel Engine	On front of intake manifold. See Fig. 8.
4.3L	On front of intake manifold. See Fig. 2.
5.0L & 5.7L - 1989	On front of intake manifold. See Fig. 3.
5.0L & 5.7L - 1990	On front of intake manifold. See Fig. 4.
7.4L - 1989	On front of intake manifold. See Fig. 5.
7.4L - 1990	On front of intake manifold. See Fig. 6.
Engine Speed Sensor (Diesel)	On right rear of engine.
Fuel Pressure Sensor (Diesel)	In fuel filter assembly. See Fig. 8.
Knock Sensor
4.3L	On left cylinder head. See Fig. 2.
5.0L & 5.7L - 1989	On lower left side of engine block, above starter. See Fig. 3.
5.0L & 5.7L - 1990	On lower left side of engine block, above starter. See Fig. 4.
7.4L
1989	On right side of engine block, above starter.
1990	On right side of engine block, above starter. See Fig. 6.
MAP Sensor (Diesel)	On right side of firewall.
MAP Sensor (Gas)
4.3L	On bracket, at center of right valve cover. See Fig. 2.
5.0L & 5.7L - 1989	On bracket, at center of right valve cover. See Fig. 3.
5.0L & 5.7L - 1990	On bracket, at center of right valve cover. See Fig. 4.
7.4L - 1989	On bracket, at center of right valve cover. See Fig. 5.
7.4L - 1990	On bracket, at center of right valve cover. See Fig. 6.
Oil Pressure Sending Unit/Switch
Diesel	On engine block, behind left cylinder head. See Fig. 8.
Gas
4.3L	On left side of engine block, above oil filter. See Fig. 2.
5.0L & 5.7L - 1989	On left side of engine block, above oil filter. See Fig. 3.
5.0L & 5.7L - 1990	On left side of engine block, above oil filter. See Fig. 4.
7.4L - 1989	On left side of engine block, above oil filter. See Fig. 5.
7.4L - 1990	On left side of engine block, above oil filter. See Fig. 6.
Oxygen Sensor
4.3L	In exhaust manifold. See Fig. 2.
5.0L & 5.7L - 1989	In exhaust manifold. See Fig. 3.
5.0L & 5.7L - 1990	In exhaust manifold. See Fig. 4.
7.4L - 1989	In exhaust manifold. See Fig. 5.
7.4L - 1990	In exhaust manifold. See Fig. 6.
Throttle Position Sensor (TPS)
4.3L	On throttle linkage. See Fig. 2.
5.0L & 5.7L - 1989	On throttle linkage. See Fig. 3.
5.0L & 5.7L - 1990	On throttle linkage. See Fig. 4.
7.4L - 1989	On throttle linkage. See Fig. 5.
7.4L - 1990	On throttle linkage. See Fig. 6.
Vehicle Speed Sensor (VSS)
4.3L	At right top of engine. See Fig. 2.
5.0L & 5.7L - 1989	At right top of engine. See Fig. 3.
5.0L & 5.7L - 1990	In dash, behind speedometer. See Fig. 4.
7.4L - 1989	At right top of engine. See Fig. 5.
7.4L - 1990	In dash, behind speedometer. See Fig. 6.
Water-In-Fuel Sensor (Diesel)	In fuel filter assembly. See Fig. 8.

Chevrolet Forward Control P30 1990 - MOTORS

Chevrolet Forward Control P30 1990 MOTORS LOCATION

Component	Location
A/C-Heater Blower Motor	On right side of firewall.
Idle Air Control (IAC) Motor
4.3L	On throttle body. See Fig. 2.
5.0L & 5.7L - 1989	On throttle body. See Fig. 3.
5.0L & 5.7L - 1990	On throttle body. See Fig. 4.
7.4L - 1989	On throttle body. See Fig. 5.
7.4L - 1990	On throttle body. See Fig. 6.
Power Door Lock Motor	At rear, in each door.
Power Window Motor	At center, in each door.
Windshield Washer Motor	On windshield washer reservoir.
Windshield Wiper Motor	On firewall.

Chevrolet Forward Control P30 1990 - SOLENOIDS & SOLENOID VALVES

Chevrolet Forward Control P30 1990 SOLENOIDS & SOLENOID VALVES LOCATION

Component	Location
Canister Purge Solenoid Valve	On vapor canister, or in vapor hose.
Cold Advance Solenoid (Diesel)	On injection pump.
Electrical Sir Control (EAC) Solenoid
4.3L (V8)	Behind air pump, on right front of engine. See Fig. 2.
4.3L (V6)	Behind air pump, on right rear of engine. See Fig. 2.
5.0L & 5.7L (V8) - 1989	Behind air pump, on right front of engine. See Fig. 3.
5.0L & 5.7L (V6) - 1989	Behind air pump, on right rear of engine. See Fig. 3.
5.0L & 5.7L (V8) - 1990	Behind air pump, on right front of engine. See Fig. 4.
5.0L & 5.7L (V6) - 1990	Behind air pump, on right rear of engine. See Fig. 4.
7.4L (V8) - 1989	Behind air pump, on right front of engine. See Fig. 5.
7.4L (V6) - 1990	Behind air pump, on right rear of engine. See Fig. 6.
EGR Dump Solenoid (Diesel)	On top left rear of engine. See Fig. 7.
EGR/EPR Solenoids (Diesel)	On top left rear of engine. See Fig. 7.
EGR Vacuum Solenoid (Gas)
4.3L	At right top of engine. See Fig. 2.
5.0L & 5.7L - 1989	At right top of engine. See Fig. 3.
5.0L & 5.7L - 1990	At right top of engine. See Fig. 4.
7.4L - 1989	At right top of engine. See Fig. 5.
7.4L - 1990	At right top of engine. See Fig. 6.
Fast Idle Solenoid (Diesel)	On injection pump.
Fuel Shutoff Solenoid (Diesel)	At top center of engine, near intake plenum.
Torque Conv. Clutch (TCC) Solenoid
5.0L & 5.7L	In automatic transmission. See Fig. 3.
7.4L - 1989	In automatic transmission. See Fig. 5.
7.4L - 1990	In automatic transmission. See Fig. 4.

Chevrolet Forward Control P30 1990 - SWITCHES

Chevrolet Forward Control P30 1990 SWITCHES LOCATION

Component	Location
A/C Pressure Cycling Switch	On rear of accumulator.
Auxiliary Fan Temp. Switch	In right cylinder head.
Back-Up Light Switch (A/T)	At base of steering column.
Back-Up Light Switch (M/T)	On left side of transmission.
Brake Pressure Warning Switch	On proportioning valve, at left frame rail.
Clutch Switch (Cruise) (M/T)	On clutch pedal bracket.
Coolant Temperature Switch	In left cylinder head.
Fuel Pump/Oil Press. Switch	On rear of intake manifold.
Glow Plug Inhibit Switch (Diesel)	On front of engine.
Hydro-Boost Flow Switch	In pressure line, at power steering pump.
Hydro-Boost Press. Warning Switch	In pressure line, behind master cylinder.
Stoplight Switch	On brake pedal bracket.
Throttle Position Switch (Diesel)	On fuel injection pump.
Transmission Kickdown Switch	At top of accelerator pedal bracket.

Chevrolet Forward Control P30 1990 - MISCELLANEOUS

Chevrolet Forward Control P30 1990 MISCELLANEOUS LOCATION

Component	Location
A/C-Heater Blower Resistors	On evaporator case, in engine compartment.
ALDL Diagnostic Connector
4.3L	Under left side of dash. See Fig. 2.
5.0L & 5.7L - 1989	Under left side of dash. See Fig. 3.
5.0L & 5.7L - 1990	Under left side of dash. See Fig. 4.
7.4L - 1989	Under left side of dash. See Fig. 5.
7.4L - 1990	Under left side of dash. See Fig. 6.
Cruise Control Servo (1989 ONLY)	On bracket, on right side of engine.
Fuel Heater (Diesel)	At fuel filter. See Fig. 8.
Fuel Pump Prime/Test Connector
4.3L	On firewall, next to fuel pump relay. See Fig. 2.
5.0L & 5.7L - 1989	On firewall, next to fuel pump relay. See Fig. 3.
5.0L & 5.7L - 1990	On firewall, next to fuel pump relay. See Fig. 4.
7.4L - 1989	On firewall, next to fuel pump relay. See Fig. 5.
7.4L - 1990	On firewall, next to fuel pump relay. See Fig. 6.
Hydro-Boost In-Line Diode	In harness, behind instrument panel.
Set Timing Connector (Gas)	In harness, near distributor.
Tachometer Connector	In harness, at ignition coil.
Vehicle Speed Sensor (VSS) Buffer	Taped to harness, behind instrument panel.