GMC S15 Pickup 1990 - ELECTRICAL COMPONENT LOCATOR 1989-91 ELECTRICAL COMPONENT LOCATIONS General Motors Corp. - Electrical Components - Trucks

GMC S15 Pickup 1990 - BUZZERS, RELAYS & TIMERS

GMC S15 Pickup 1990 BUZZERS, RELAYS & TIMERS LOCATION

Component	Location
A/C Clutch Control Relay
2.5L & 4.3L	Far left side of the firewall. See Fig. 1 .
2.8L	Center of left side inner fender. See Fig. 2 .
A/C High Blower Relay	On right side of firewall, between blower motor and accumulator.
Fuel Pump Relay
2.5L	On left front fender panel. See Fig. 1 .
2.8L	On left front fender panel. See Fig. 2 .
4.3L	On left front fender panel. See Fig. 3 .
Hazard Flasher Relay	On convenience center.
Horn Relay	On convenience center.
Rear Window Defogger Relay	Under left side of dash, on brake pedal support bracket.
Rear Window Release Relay	On bracket, on left side of steering column.
Turn Signal Flasher Relay	On fuse block.

GMC S15 Pickup 1990 CIRCUIT PROTECTION DEVICES LOCATION

Component	Location
Circuit Breakers
Power Accessories	In fuse block, at top.
Power Windows	In fuse block, at bottom.
Convenience Center	Left of steering column, at lower edge of dash.
Fuse Block
2.5L	Below left side of dash. See Fig. 1 .
2.8L	Below left side of dash. See Fig. 2 .
4.3L	Below left side of dash. See Fig. 3 .
Fusible Links
Power Distribution (2.5L & 4.3L)	At rear of alternator (2 links).
Power Distribution (2.8L)	At starter solenoid.
Interior Lights In-line Fuse	On center of firewall.

GMC S15 Pickup 1990 CONTROL UNITS LOCATION

Component	Location
Audio Alarm Module	On convenience center.
Cruise Control Module	On left side of brake pedal bracket.
Digital Ratio Adapter Controller	Under right side of dash, next to ECM.
Elapsed Timer Module	Under right side of dash, next to ECM. See Fig. 2 .
Electronic Control Module (ECM)
2.5L	Under right side of dash. See Fig. 1 .
2.8L	Under right side of dash. See Fig. 2 .
4.3L	Under right side of dash. See Fig. 3 .
Electronic Spark Control (ESC) Module
2.8L	On center of firewall. See Fig. 2 .
4.3L	On center of firewall. See Fig. 3 .
RABS Electronic Control Unit	On bracket, at master cylinder.
Windshield Wiper Module	Inside windshield wiper motor.

GMC S15 Pickup 1990 SENDING UNITS & SENSORS LOCATION

Component	Location
Coolant Temp. Sending Unit/Switch
2.5L	On left rear corner of cylinder head.
2.8L	On left front corner of left cylinder head.
4.3L	On right side of engine block.
Coolant Temperature Sensor
2.5L	On thermostat housing. See Fig. 1 .
2.8L	On front left corner of intake manifold. See Fig. 2 .
4.3L	Top front of engine. See Fig. 3 .
Knock Sensor
2.8L	On right side of engine block. See Fig. 2 .
4.3L	Behind left cylinder head. See Fig. 3 .
Manifold Absolute Press. (MAP) Sensor
2.5L	On air cleaner housing. See Fig. 1 .
2.8L	On air cleaner housing. See Fig. 2 .
4.3L	On air cleaner housing. See Fig. 3 .
Manifold Air Temp. (MAT) Sensor	On front of intake manifold. See Fig. 1 .
Oil Pressure Sending Unit/Switch
2.5L	At oil filter flange. See Fig. 1 .
2.8L	At oil filter flange. See Fig. 2 .
4.3L	On top rear of engine. See Fig. 3 .
Oxygen Sensor
2.5L	In exhaust manifold, or exhaust pipe. See Fig. 1 .
2.8L	In exhaust manifold, or exhaust pipe. See Fig. 2 .
4.3L	In exhaust manifold, or exhaust pipe. See Fig. 3 .
RABS Speed Sensor	Part of VSS.
Throttle Position Sensor (TPS)
2.5L	On throttle body. See Fig. 1 .
2.8L	On throttle body. See Fig. 2 .
4.3L	On throttle body. See Fig. 3 .
Vehicle Speed Sensor (VSS)
2.5L	In speedometer housing. See Fig. 1 .
2.8L	In speedometer housing. See Fig. 2 .
4.3L	In speedometer housing. See Fig. 3 .

GMC S15 Pickup 1990 MOTORS LOCATION

Component	Location
A/C-Heater Blower Motor	In evaporator housing, in engine compartment.
Idle Air Control (IAC) Motor
2.5L	On throttle body. See Fig. 1 .
2.8L	On throttle body. See Fig. 2 .
4.3L	On throttle body. See Fig. 3 .
Power Door Lock Motor	In bottom rear of each door.
Power Window Motor	In each door.
Windshield Washer Motor	In bottom of washer reservoir.
Windshield Wiper Motor	On center of firewall.

GMC S15 Pickup 1990 SOLENOIDS & SOLENOID VALVES LOCATION

Component	Location
EGR Solenoid Valve
2.5L	On bracket, at right front corner of engine. See Fig. 1 .
2.8L	At EGR valve. See Fig. 2 .
4.3L	On bracket, at center of right valve cover. See Fig. 3 .
Electric Air Control (EAC) Solenoid (2.8L)	On bracket, at right front of engine. See Fig. 2 .
Elect. Vacuum Regulator Valve (EVRV)
2.5L	On right front of intake manifold.
2.8L	On left rear of intake manifold.
4.3L	On right valve cover.
Rear Window Release Solenoid	In center of tailgate.

GMC S15 Pickup 1990 SWITCHES LOCATION

Component	Location
A/C Low Charge Protection Switch	On rear of A/C compressor.
A/C Pressure Cycling Switch	On accumulator.
Back-Up Light Switch	On left side of transmission.
Brake Pressure Switch	On master cylinder.
Brake/Stoplight Switch	On pedal bracket.
Brake Switch (Cruise)	On brake pedal support bracket.
Clutch Switch (Cruise)	On clutch pedal support bracket.
EGR Diagnostic Switch (2.8L)	At left rear of engine, next to EGR valve. See Fig. 2 .
Parking Brake Switch	On base of parking brake assembly.
Power Steering Press. Switch (PSPS)	In power steering pressure hose, near steering gear. See Fig. 1 .
Starter Lock-Out Switch (M/T)	On clutch pedal bracket.
Starter Lock-Out Switch (A/T)	Base of steering column.
Transmission Position Switch	On steering column.
4WD Indicator Switch	On front drive axle.

GMC S15 Pickup 1990 MISCELLANEOUS LOCATION

Component	Location
A/C-Heater Blower Motor Resistor	On blower motor housing.
ALDL Diagnostic Connector
2.5L	Under left side of dash, to right of steering column. See Fig. 1 .
2.8L	Under left side of dash, to right of steering column. See Fig. 2 .
4.3L	Under left side of dash, to right of steering column. See Fig. 3 .
Cruise Control Servo (1989 ONLY)	On top of left front wheelwell.
Fuel Pump Prime/Test Connector
2.5L	On center of firewall. See Fig. 1 .
2.8L	On left fender panel, behind fuel pump relay. See Fig. 2 .
4.3L	On left fender panel, behind fuel pump relay. See Fig. 3 .