Contents Wiring diagrams Section: Electrical Component Locations All sections

Electrical Component Locator: Other GMC Forward Control P3500

BUZZERS, RELAYS & TIMERS

ComponentLocation
A/C-Heater Blower RelaysOn evaporator case, in engine compartment.
Auxiliary Cooling Fan Relay
"G" SeriesOn radiator support panel.
"P" SeriesOn top of shipping panel.
Brake Warning Alarm BuzzerBehind left side of dash.
Cold Advance Control Relay (6.2L Diesel)On left front of engine compartment. (Схема №1)
Daytime Running Lights (DRL) RelayBehind left side of dash.
Fuel Pump Relay
"G" Series
4.3L (VIN Z)At center of firewall. (Схема №2)
5.0L (VIN H) & 5.7L (VIN K)At center of firewall. (Схема №3)
7.4L (VIN N)At center of firewall. (Схема №4)
"P" Series
4.3L (VIN Z)On left frame rail, behind shipping panel. (Схема №5)
5.7L (VIN K)On left frame rail, behind shipping panel. (Схема №6)
7.4L (VIN N)On left frame rail, behind shipping panel. (Схема №7)
Hazard Flasher
"G" SeriesNear interior fuse block.
"P" SeriesAt top left side of shipping panel.
Horn RelayNear interior fuse block.
Power Antenna RelayOn right side of steering column.
Power Door Lock Delay RelayBehind left side of dash, above kick panel.
Power Door Lock RelayBehind left side of dash, above kick panel.
Rear Defogger RelayOn brake pedal support bracket.
Turn Signal FlasherOn fuse block.

BUZZERS, RELAYS & TIMERS LOCATION

CIRCUIT PROTECTION DEVICES

ComponentLocation
Circuit Breakers
Power WindowOn fuse block.
Power AccessoryOn fuse block.
Fuse Block
4.3L (VIN Z)
"G" SeriesUnder left side of dash, above kick panel. (Схема №2)
"P" SeriesUnder left side of dash, above kick panel. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)Under left side of dash, above kick panel. (Схема №3)
5.7L (VIN K) "P" SeriesUnder left side of dash, above kick panel. (Схема №6)
7.4L (VIN N)
"G" SeriesUnder left side of dash, above kick panel. (Схема №4)
"P" SeriesUnder left side of dash, above kick panel. (Схема №7)
Fusible Links
A/C-Heater (Rust)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)At battery junction block.
Ignition Switch (Rust)At battery junction block (2 links).
Power Accessories (Rust)At battery junction block.
In-Line Fuse (MT1 Trans.)Behind left side of dash.

CIRCUIT PROTECTION DEVICES LOCATION

CONTROL UNITS

ComponentLocation
Audio Alarm ModuleBehind dash, below fuse block.
Check Engine Light Driver ModuleOn left side of steering column.
Cruise Control ModuleAt rear of parking brake bracket.
Daytime Running Lights (DRL) ModuleBehind left side of dash.
Diode Array ModuleBehind left side of dash, in dash harness.
Electronic Control Module (ECM)
4.3L (VIN Z)
"G" SeriesUnder driver's seat. (Схема №2)
"P" SeriesUnder driver's seat. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)Under driver's seat. (Схема №3)
Electronic Control Module (ECM)
"P" Series 5.7L (VIN K)Under driver's seat. (Схема №6)
"G" Series 7.4L (VIN N)Under driver's seat. (Схема №4)
"P" Series 7.4L (VIN N)Under driver's seat. (Схема №7)
"G" & "P" Series 6.2L (Diesel)Under driver's seat. (Схема №1)
Electronic Delay ModuleBehind left side of dash.
Elec. Spark Control (ESC) Module
4.3L (VIN Z)
"G" SeriesUnder driver's seat. (Схема №2)
"P" SeriesUnder driver's seat. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)Under driver's seat. (Схема №3)
"P" Series 5.7L (VIN K)Under driver's seat. (Схема №6)
Electronic Spark Timing ModuleOn distributor.
Glow Plug Controller
"G" SeriesOn left side of engine.
"P" SeriesOn top rear of engine.
Hot Fuel Module
5.0L (VIN H) & 5.7L (VIN K)Under driver's seat. (Схема №3)
7.4L (VIN N)
"G" SeriesUnder driver's seat. (Схема №4)
"P" SeriesUnder driver's seat. (Схема №7)
Keyless Entry ModuleBehind right side of dash.
Low Coolant Warning ModuleBehind left side of dash.
Power Door Lock Delay ModuleTo right of steering column.
Powertrain Control Module (PCM)
"G" SeriesUnder driver's seat.
"P" SeriesBehind left side of shipping panel.
Rear ABS ModuleOn left side of engine compartment.
Transmission Control Module
"G" SeriesUnder driver's seat.
"P" SeriesBehind left side of shipping panel.

CONTROL UNITS LOCATION

SENDING UNITS & SENSORS

ComponentLocation
Barometric Pressure SensorAt center of shipping.
Coolant Level SensorIn radiator.
Coolant Temp. Sending UnitOn left cylinder head.
Coolant Temperature Sensor
4.3L (VIN Z)
"G" SeriesOn front of intake manifold. (Схема №2)
"P" Series 4.3L (VIN Z)On front of intake manifold. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On front of intake manifold. (Схема №3)
"P" Series 5.7L (VIN K)On front of intake manifold. (Схема №6)
Coolant Temperature Sensor
"G" Series 7.4L (VIN N)On front of intake manifold. (Схема №4)
"P" Series 7.4L (VIN N)On front of intake manifold. (Схема №7)
Engine Speed Sensor
"G" SeriesOn left front of engine.
"P" Series 6.2L (Diesel)On rear of engine. (Схема №1)
Input Speed SensorOn left side of transmission.
Knock Sensor
"G" Series 4.3L (VIN Z)Under exhaust manifold. (Схема №2)
"P" Series 4.3L (VIN Z)Under exhaust manifold. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)Near starter. (Схема №3)
"P" Series 5.7L (VIN K)Near starter. (Схема №6)
Low Coolant Warning Sensor (Diesel)In right radiator tank.
Manifold Abs. Press. (MAP) Sensor
"G" & "P" Series 6.2L (Diesel)On center of firewall. (Схема №1)
Gas
"G" Series 4.3L (VIN Z)At center of right valve cover. (Схема №2)
"P" Series 4.3L (VIN Z)At center of right valve cover. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)At center of right valve cover. (Схема №3)
"P" Series 5.7L (VIN K)At center of right valve cover. (Схема №6)
"G" Series 7.4L (VIN N)At center of right valve cover. (Схема №4)
"P" Series 7.4L (VIN N)At center of right valve cover. (Схема №7)
Oil Pressure Sending UnitOn left rear of engine block.
Output Speed SensorOn left side of transmission.
Throttle Position Sensor (TPS)
"G" Series 4.3L (VIN Z)On throttle body (gas), or on injection pump (diesel). (Схема №2)
"P" Series 4.3L (VIN Z)On throttle body (gas), or on injection pump (diesel). (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On throttle body (gas), or on injection pump (diesel). (Схема №3)
"P" Series 5.7L (VIN K)On throttle body (gas), or on injection pump (diesel). (Схема №6)
"G" Series 7.4L (VIN N)On throttle body (gas), or on injection pump (diesel). (Схема №4)
"P" Series 7.4L (VIN N)On throttle body (gas), or on injection pump (diesel). (Схема №7)
"G" & "P" Series 6.2L (Diesel)On throttle body (gas), or on injection pump (diesel). (Схема №1)
Vehicle Speed Sensor (VSS)
"G" Series 4.3L (VIN Z)On left rear of transmission. (Схема №2)
"P" Series 4.3L (VIN Z)On left rear of transmission. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On left rear of transmission. (Схема №3)
"P" Series 5.7L (VIN K)On left rear of transmission. (Схема №6)
"G" Series 7.4L (VIN N)On left rear of transmission. (Схема №4)
"P" Series 7.4L (VIN N)On left rear of transmission. (Схема №7)
"G" & "P" Series 6.2L (Diesel)On left rear of transmission. (Схема №1)
Water-In-Fuel Sensor (Diesel)In fuel filter assembly.

SENDING UNITS & SENSORS LOCATION

MOTORS

ComponentLocation
Idle Air Control (IAC) Motor
4.3L (VIN Z)
"G" SeriesOn throttle body (gas). (Схема №2)
"P" SeriesOn throttle body (gas). (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On throttle body (gas). (Схема №3)
"P" Series 5.7L (VIN K)On throttle body (gas). (Схема №6)
"G" Series 7.4L (VIN N)On throttle body (gas). (Схема №4)
Idle Air Control (IAC) Motor ("P" Series 7.4L VIN N)On throttle body (gas). (Схема №7)
Windshield Washer Pump MotorOn windshield washer reservoir.
Windshield Wiper MotorOn firewall.

MOTORS LOCATION

SOLENOIDS & SOLENOID VALVES

ComponentLocation
Cold Advance Solenoid (Diesel)On injection pump.
Electric Air Control (EAC) Solenoid ("G" Series 4.3L VIN Z)On left rear of engine, on valve cover. (Схема №2)
Elec. Vacuum Regulator Valve (EVRV)
5.0L (VIN H) & 5.7L (VIN K)On top right side of engine. (Схема №3)
"P" Series 5.7L (VIN K)On top right side of engine. (Схема №6)
"G" Series 7.4L (VIN N)On top right side of engine. (Схема №4)
"P" Series 7.4L (VIN N)On top right side of engine. (Схема №7)
EGR Vacuum Solenoid
"G" Series 4.3L (VIN Z)On top right of engine. (Схема №2)
"P" Series 4.3L (VIN Z)On top right of engine. (Схема №5)
"G" & "P" Series 6.2L (Diesel)At left rear of engine. (Схема №1)
Except 4.3L & DieselOn left front of engine.
EGR Vent Solenoid (6.2L Diesel)On top left rear of engine. (Схема №1)
EPR Solenoids (6.2L Diesel)On left front of engine. (Схема №1)
Fast Idle Solenoid (6.2L Diesel)On injection pump. (Схема №1)
Fuel Shutoff Solenoid (Diesel)At top center of engine, near intake plenum.
Torque Conv. Clutch (TCC) Solenoid
"G" Series 4.3L (VIN Z)In transmission. (Схема №2)
"P" Series 4.3L (VIN Z)In transmission. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)In transmission. (Схема №3)
"P" Series 5.7L (VIN K)In transmission. (Схема №6)
"G" Series 7.4L (VIN N)In transmission. (Схема №4)
"P" Series 7.4L (VIN N)In transmission. (Схема №7)
"G" & "P" Series 6.2L (Diesel)In transmission. (Схема №1)

SOLENOIDS & SOLENOID VALVES LOCATION

SWITCHES

ComponentLocation
A/C Clutch Cycling Press. SwitchOn rear of accumulator.
A/C High Pressure Cut-Out SwitchOn rear of compressor.
Aux. Cooling Fan Press. SwitchOn right side of engine block, above starter.
Backup Light Switch (A/T)At base of steering column.
Brake Pressure Warning SwitchOn proportioning valve, at left frame rail.
Cold Advance Fast Idle Temp. SwitchOn rear of right cylinder head.
Cold Advance Glow Plug Inhibit RelayOn right side of firewall.
Coolant Temperature SwitchIn left cylinder head.
Engine Temperature SwitchOn rear of right cylinder head.
Flow SwitchNear power steering pump.
Fuel Pump/Oil Press. SwitchNear distributor.
Low Coolant Warning SwitchOn right side of radiator.
Neutral Safety SwitchOn lower steering column.
Oil Pressure Switch
"G" Series 4.3L (VIN Z)On top rear of engine. (Схема №2)
"P" Series 4.3L (VIN Z)On top rear of engine. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On top rear of engine. (Схема №3)
"P" Series 5.7L (VIN K)On top rear of engine. (Схема №6)
"G" Series 7.4L (VIN N)On top rear of engine. (Схема №4)
"P" Series 7.4L (VIN N)On top rear of engine. (Схема №7)
Stoplight SwitchOn brake pedal bracket.

SWITCHES LOCATION

MISCELLANEOUS

ComponentLocation
A/C-Heater Blower ResistorsOn evaporator case, in engine compartment.
ALDL Diagnostic Connector
"G" Series 4.3L (VIN Z)Under left side of dash. (Схема №2)
"P" Series 4.3L (VIN Z)Under left side of dash. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)Under left side of dash. (Схема №3)
"P" Series 5.7L (VIN K)Under left side of dash. (Схема №6)
"G" Series 7.4L (VIN N)Under left side of dash. (Схема №4)
"P" Series 7.4L (VIN N)Under left side of dash. (Схема №7)
"G" & "P" Series 6.2L (Diesel)Under left side of dash. (Схема №1)
Fuel Heater (Diesel)At fuel filter assembly.
Fuel Pump Prime/Test Connector
"G" Series 4.3L (VIN Z)On firewall, next to fuel pump relay. (Схема №2)
"P" Series 4.3L (VIN Z)On firewall, next to fuel pump relay. (Схема №5)
5.0L (VIN H) & 5.7L (VIN K)On firewall, next to fuel pump relay. (Схема №3)
"P" Series 5.7L (VIN K)On firewall, next to fuel pump relay. (Схема №6)
"G" Series 7.4L (VIN N)On firewall, next to fuel pump relay. (Схема №4)
"P" Series 7.4L (VIN N)On firewall, next to fuel pump relay. (Схема №7)
In-Line Diode
"G" SeriesOn top rear of engine.
"P" SeriesNear A/C compressor.
Low Coolant ProbeOn right side of radiator.
Rear Heater Blower ResistorBehind driver's seat, on heater case.
Vehicle Speed Sensor (VSS) Buffer
"G" SeriesTaped to harness, behind instrument panel.
"P" Series 5.7L (VIN K)Inside left side of shipping panel. (Схема №6)

MISCELLANEOUS LOCATION