GMC Forward Control P3500 (1985-1999) gry Wiring diagrams

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID A/T ISS HI IN A/T ISS LO IN AUTO TRANSMISSION INPUT SHAFT SPEED SENSOR (INSIDE FRONT OF TRANSMISSION) AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE DK BLU/WHT WIRE ECM BATT FUSE ECM I FUSE ECT SENS INPUT ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP FRONT OF ENGINE) FUSE GAUGES FUSE GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR PPL/WHT WIRE PRESS CTRL SOLENOID RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TCC PWM SOL TCC PWM SOLENOID TCC/STOP- LAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS TEMP SIG IN VEHICLE CONTROL MODULE (VCM) (BEHIND LEFT HEADLIGHT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION) VSS HI VSS LO YEL WIRE YEL/BLK WIRE

4 13 PNK WIRE A/T ABS IND. ACCY BULB TEST LOCK OFF ANTI-LOCK BRAKES SYSTEM AUTO PARK IND. BLK WIRE BLK/WHT WIRE BRAKE IND DRL IND BRN/WHT WIRE CHECK GAUGES IND COOLANT TEMPERATURE GAUGE DIESEL DK BLU WIRE DK GRN WIRE DOOR AJAR IND ECM 1 FUSE 12 ENGINE CONTROLS OR STARTING/ CHARGING SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE CONTROLS SYSTEM ENGINE COOLANT LEVEL SWITCH (ON LOWER LEFT END OF RADIATOR SURGE TANK) FUEL GAUGE FUEL SENDER (ON TOP OF FUEL TANK) GAS GAUGES FUSE 8 GRY WIRE GRY/BLK WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IGNITION SWITCH ILLUMINATION IN-LINE CONNECTOR PROVISIONS FOR BODY BUILDER INSTRUMENT CLUSTER INTERIOR LIGHTS SYSTEM WARNING SYSTEMS LEFT TURN IND LOW COOLANT IND LT BLU WIRE LT GRN (OR WHT) WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION IND. LAMP (MIL) (SERVICE ENGINE SOON IND) OIL PRESSURE GAUGE PNK WIRE PPL PPL DIESEL PPL GAS PPL RIGHT TURN IND RUN WIRE SEAT BELT IND SERVICE THROTTLE SOON IND SPEEDOMETER TACHOMETER TAN WIRE TAN/WHT WIRE VEHICLE CONTROL MODULE (ON LEFT SIDE OF RADIATOR SUPPORT) VOLTMETER VSS CALIBRATOR (LEFT SIDE OF DRIVER'S ISLAND, UNDER RELAY BRACKET) WAIT TO START IND WATER IN FUEL IND WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1996 VFTC A/C COMPRESSOR CLUTCH RELAY AUXILIARY ENGINE COOLANT FAN RELAY (DIESEL ONLY) BATT BUS BATTERY BATTERY JUNCTION BLOCK (LEFT SIDE OF ENGINE BULKHEAD, ABOVE RELAY BRACKET) BLK WIRE DATA LINK CONNECTOR (DLC) DIESEL DOME LAMP (PROVISIONS FOR) ECM BAT FUSE ENG-BAT FUSE FUEL PUMP RELAY FUEL PUMP SWITCH, ENGINE OIL PRESSURE GAUGE SENSOR FUSIBLE LINK (10 GA-RUST) FUSIBLE LINK (16 GA- FUSIBLE LINK 12 GA. BLUE FUSIBLE LINK 18 GA. BLUE FUSIBLE LINK 18 GA. RUST GAS GENERATOR (RIGHT FRONT OF ENGINE) GLOW PLUG CONTROL SWITCH (DIESEL ONLY) GRY WIRE HAZARD WARNING LAMPS FLASHER HEADLAMPS SWITCH HORN RELAY HORN/ DM FUSE TAIL LPS FUSE I/P FUSE BLOCK (DASH PANEL PROVIDED BY BODY BUILDER) (BODY BUILDER INSTALLED) IGNITION SWITCH ORG/ WIRE PWR BUS PWR FUSE RED WIRE REMOTE BATTERY ACCESS TERMINAL BLOCK (REAR OF RIGHT RADIATOR CORE SUPPORT PANEL) SEAT BELT ALARM SECONDARY BATTERY (DIESEL ONLY) STARTER RELAY STARTER SOLENOID (AT STARTER, LOWER RIGHT SIDE OF ENGINE) STOP/ HAZ FUSE STUD TO HEADLAMPS SWITCH (CAVITY E) TORQUE CONVERTER CLUTCH, STOPLAMPS SWITCH TRANSMISSION CONTROL MODULE (A/T ONLY) VEHICLE CONTROL MODULE (VCM) W/DELUXE SCHOOL BUS

1996 VFTC 7.20 +/- 1.20 OHMS BRN WIRE DASH LAMPS INPUT DK GRN WIRE FROM I/P FUSE BLOCK (TAIL LAMPS FUSE) GRY WIRE HEAD OFF PARK HEADLAMPS SWITCH I/P LAMPS DIMMER SWITCH INSTRUMENT CLUSTER LICENSE LAMPS, LEFT REAR LICENSE LAMPS, RIGHT REAR MARKER LAMPS (PROVISIONS FOR) ORG/ WIRE PANEL ILLUMINATION PANEL LAMPS SWITCH PARK PARK, TURN SIGNAL (T/S) LAMP LEFT FRONT PARK, TURN SIGNAL (T/S) LAMP RIGHT FRONT PRNDL LAMP SEAT BELT ALARM SIDE MARKER LAMP LEFT FRONT SIDE MARKER LAMP RIGHT FRONT SIDE MARKER LAMP, LEFT REAR (PROVISIONS FOR) SIDE MARKER LAMP, RIGHT REAR (PROVISIONS FOR) TAIL TAIL, STOP/TURN SIGNAL LAMPS LEFT (PROVISIONS FOR) TAIL, STOP/TURN SIGNAL LAMPS RIGHT (PROVISIONS FOR)

1996 VFTC BRN WIRE DK GRN WIRE FROM I/P FUSE BLOCK (TAIL LAMPS FUSE) FULL DIM GRY WIRE HEAD OFF PARK HEADLAMPS SWITCH I/P FUSE BLOCK (MOUNTED ON I/P) I/P FUSE BLOCK (MOUNTED ON THE I/P) INSTR- LPS FUSE INSTRUMENT CLUSTER INSTRUMENT PANEL DIMMER SWITCH LAMP ON INPUT LICENSE LAMP, LEFT REAR (PROVISIONS FOR) LICENSE LAMP, RIGHT REAR (PROVISIONS FOR) LIGHT SWITCH ORG/ WIRE PANEL ILLUMINATION PANEL LAMPS PARK PARK, TURN SIGNAL (T/S) LAMP LEFT FRONT PARK, TURN SIGNAL (T/S) LAMP RIGHT FRONT ROOF MARKER LAMPS (PROVISIONS FOR) SEATBELTS/ LAMPS ALARM MODULE SIDE MARKER LAMP LEFT FRONT (PROVISIONS FOR) SIDE MARKER LAMP RIGHT FRONT (PROVISIONS FOR) SIDE MARKER LAMP, LEFT REAR (PROVISIONS FOR) SIDE MARKER LAMP, RIGHT REAR (PROVISIONS FOR) TAIL, STOP, TURN SIGNAL (T/S) LAMPS, LEFT (PROVISIONS FOR) TAIL, STOP, TURN SIGNAL (T/S) LAMPS, RIGHT (PROVISIONS FOR) TRANSMISSION RANGE INDICATOR LAMP

A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (ON REAR OF A/C COMPRESSOR) BLK WIRE BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD RELAYS) BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 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) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN AND START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE 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 WIRE OIL PRESS GAUGE ORG/ WIRE PNK 22 23 WIRE PNK PNK 2 3 WIRE PNK PNK WIRE PNK WIRE PPL PPL PNK 9 10 11 12 13 14 15 WIRE RED WIRE RED/BLK WIRE SPEED METER TACH TAN WIRE THROTTLE POSITION SENSOR (ON THROTTLE BODY, TOP OF ENGINE) TRANS FUSE 17 WHT WIRE YEL WIRE

1 2 3 4 5 6 7 8 PNK PNK WIRE A/C COMP CYL SW A/C REQUEST SIGNAL AIR CONDITIONING SYSTEM ANTI-LOCK BRAKES SYSTEM PPL AUX ELECT COOLING FAN BRAKE SIGNAL SERIAL DATA PPL PPL 420 1807 B(+) BATTERY FEED RANGE SIGNAL B RANGE SIGNAL A 1225 1224 PNK WIRE BLK RED/ WIRE BLK WIRE BLK/WHT WIRE BLU/ WHT WIRE BLU/WHT WIRE BRN WIRE BRN/WHT WIRE COOLING FANS SYSTEM CRUISE CONTROL MODULE (ON RADIATOR SUPPORT BRACKET) CRUISE CTRL ENGAGED CRUISE ENGAGED SIG CYLINDER 1 CYLINDER 4 CYLINDER 5 CYLINDER 3 CYLINDER 6 CYLINDER 7 CYLINDER 2 CYLINDER 8 DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM B FUSE 6 EGR VALVE FEED EGR VLV CTRL ELEC SPK TIMING CTRL SIGNAL EST CTRL FUEL PMP RLY CTRL 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (LEFT SIDE OF ENGINE COMPT) GRN WIRE GROUND GRY WIRE HIGH VOLTAGE COIL WIRE HOT AT ALL TIMES HOT IN RUN I-3 FUSE 9 I/P FUSE BLOCK IGN FEED IGNITION COIL (ON BRACKET AT REAR OF INTAKE PLENUM) IGNITION COIL MODULE (ON BRACKET AT REAR OF INTAKE PLENUM) LT BLU/BLK WIRE LT BLU/WHT WIRE ORG/ WIRE PCS HIGH INPUT SPEED SENS LOW INPUT SPEED SENS HIGH IC CNTRL PCS LOW GROUND GROUND SENS GROUND PNK 22 23 WIRE PNK IGN FEED WIRE PNK WIRE PPL PPL DATA LINK CONNECTOR (DLC) (BELOW DASH, NEAR STEERING COLUMN) 4 5 PPL FUEL LEVEL MODULE A/C REC PPL TCC/STOPLAMP INPUT RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SPARK PLUGS SPEED SENSOR INPUT VEHICLE CONTROL MODULE (VCM) (ON CENTER FRONT OF ENGINE COMPARTMENT) VSS OUTPUT SIGNAL VSS OUTPUT SIGNAL CHECK ENGINE LP CTRL 389 419 WHT DK GRN/ WIRE WHT WIRE WHT/BLK WIRE

1223 1222 SHIFT SOL B OUT SHIFT SOL A OUT HIGH IDLE SW OUT 3-2 CTRL OUT 1225 1226 419 RANGE MODE SEL B RANGE MODE SEL C SERV ENG SOON IND CTRL 465 1229 FUEL PMP RLY CTRL FORCE MOTOR HI 470 OR 452 496 1456 KNOCK SENS INPUT EGR INPUT A/T INPUT SPEED SENSOR (ON AUTO TRANSMISSION LEFT CENTER) BLK WIRE BLK/RED WIRE BLK/WHT WIRE BLU WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR) BRN WIRE BRN/WHT WIRE BYPASS 5 VOLTS SENS GROUND SENS GROUND TRANS TEMP INPUT DIAG ENABLE-POWERTRAIN TP SENS IN DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECT SENS INPUT EGR SOL OUT ELECTRONIC 4-SPD AUTOMATIC OVERDRIVE TRANSMISSION EVAPORATIVE CANISTER PURGE SOLENOID (TOP LEFT CENTER OF INTAKE MANIFOLD) FUEL INJ CTRL GRN WIRE GRY WIRE HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE AIR CONTROL VALVE MOTOR (ON LEFT SIDE OF THROTTLE BODY INTAKE) KNOCK SENSOR (KS) (ON RIGHT SIDE OF ENGINE BLOCK AHEAD OF STARTER) LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE LT LT LT PNK PNK WIRE OIL PRESS INPUT MAP SENS INPUT ORG/ WIRE OXYGEN SENSOR (IN EXHAUST STREAM AHEAD OF MUFFLER) PCM GROUND PNK IGNITION CAN PURGE SOL OUT WIRE PNK PNK 26 27 WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (ON LEFT SIDE OF DRIVER'S ISLAND) PPL PPL 16 17 18 19 PPL 420 474 BRAKE SW INPUT PPL/WHT WIRE RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SHIFT SOL. SHIFT SOL. SHIFT SOL. SHIFT SOL. FORCE MOTOR TAN WIRE TAN/BLK WIRE TRANS FUSE TRANS TEMP WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

4 7 8 9 11 12 13 15 VSS OUT VSS RETURN GROUND BLK WIRE BLK/RED WIRE BREAKOUT FOR ENGINE COOLANT FAN MOTOR, TOWARD CRUISE CONTROL MODULE) BRN WIRE BRN/WHT WIRE CONTACT CRUISE CONTROL MODULE (ON RADIATOR SUPPORT BRACKET) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM BAT FUSE ENG 1 FUSE ENGINE COOLANT TEMPERATURE SENSOR (FRONT, CENTER OF ENGINE COOLANT INTAKE) FROM BREAKOUT FOR CRUISE CONTROL MODULE, TOWARD ENG) FROM BREAKOUT FOR GENERATOR) GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN, START (CRANK) I-3 FUSE I/P FUSE BLOCK (MOUNTED ON THE I/P) IDLE SPEED CONTROL ACTUATOR (ON THROTTLE BODY) LEFT BULK- HEAD GROMMET UNDER I/P) LINEAR EGR SOLENOID VALVE (NO COMPONENT LOCATION AVAILABLE) LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK PNK 26 27 WIRE PNK WIRE PPL PPL 16 17 18 19 PPL TCC/STOPLAMP INPUT PPL/WHT WIRE RED WIRE TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (ON LEFT SIDE OF THROTTLE BODY) VEHICLE SPEED SENSOR (ON LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (ON DRIVER'S ISLAND SUPPORT ABOVE ACCELERATOR PEDAL) VSS VSS LO VSS SIG VSS HI SECOND. VSS WHT WIRE YEL WIRE

BATTERY JUNCTION BLOCK (ON FORWARD LEFT SIDE OF BULKHEAD) BLK WIRE BLK/RED WIRE BRN WIRE BRN/WHT WIRE BYPASS DIST. REF HI DIST. REF LO DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE FUEL GAUGE FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (AT RELAY CENTER RIGHT SIDE OF MAIN SUPPORT AT DRIVER'S ISLAND) FUEL PUMP, SENDER (ON TOP OF FUEL TANK) FUSIBLE LINK (16 GA- GAUGES FUSE GRY WIRE HIGH VOLTAGE IGNITION COIL WIRE HOT AT ALL TIMES HOT IN RUN, START (CRANK) I/P FUSE BLOCK (MOUNTED ON THE I/P) IGNITION COIL (ON BRACKET AT REAR OF INTAKE PLENUM) IGNITION MODULE IGNITION SWITCH INSTRUMENT CLUSTER LOCK OFF OIL PRESS GAUGE ORG/ WIRE PICKUP COIL PNK 9 10 11 12 13 14 15 16 WIRE PNK PNK 1 2 3 4 5 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR SPEED METER TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE BODY FUEL INJECTOR NO.1 (ON TOP OF INTAKE MANIFOLD) THROTTLE BODY FUEL INJECTOR NO.2 (ON TOP OF INTAKE MANIFOLD) WHT WIRE