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

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 SHIFT SOL 3-2 SHIFT SOLENOID A/C COMPRESSOR RELAY, GENERATOR PNK WIRE A/T INPUT SPEED SENSOR (LEFT SIDE OF TRANSMISSION) A/T ISS SENS HI IN A/T ISS SENS LO IN APP 1 SIGNAL IN APP 2 SIGNAL IN APP 3 SIGNAL IN AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BRAKE SWITCH IN BRN WIRE BRN/WHT WIRE BUSS BAR CLASS II DATA DATA LINK CONNECTOR (PARTIAL) (BELOW DASH, NEAR STEERING COLUMN) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ECM-BAT FUSE 6 ECT SENSOR IN ELECTRONIC BRAKE CONTROL MODULE ENGINE COOLANT TEMPERATURE SENSOR (TOP FRONT OF ENGINE) FUEL PUMP RELAY, ENGINE OIL PRESSURE INDICATOR SENSOR GAUGES FUSE 8 GRY WIRE HAZARD LAMPS FLASHER (ABOVE STEERING COLUMN) HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START I-3 FUSE 9 I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DRIVER'S ISLAND) PPL PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE SENSOR GROUND SERVICE ENGINE SOON INDICATOR STOP-HAZ FUSE 11 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 TWISTED WIRE PAIR 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 YEL WIRE YEL/BLK WIRE

7.4L BACKUP LAMPS CIRCUIT BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE COOLING FAN NOTOR HARN BREAKOUT) CRUISE CONTROL SYSTEM DK BLU WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM GRN WIRE HAZARD HAZARD LAMPS FLASHER (INNER LEFT SIDE OF MAIN SUPPORT BRACKET) HEAD OFF HEADLAMP BREAKOUT) HEADLAMP SWITCH CONNECTOR) HEADLAMPS SWITCH HOT AT ALL TIMES HOT IN I/P FUSE BLOCK INSTRUMENT CLUSTER RIGHT TURN INDIC INTERIOR LAMPS SYSTEM LEFT FRONT PARK, TURN SIGNAL (T/S) LAMP LEFT FRONT SIDE MARKER LAMP LEFT HEAD- LAMP BREAKOUT) LEFT HEADLAMP BREAKOUT) LEFT REAR SIDE MARKER LAMP LEFT TURN INDIC LT BLU WIRE NCA WIRE NORMAL ORG/ WIRE PARK PARK TURN PPL 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 SIDE MARKER LAMP RIGHT REAR LICENSE LAMP LEFT REAR LICENSE LAMP RUN WIRE STOP-HAZ FUSE 11 TAIL LAMPS FUSE 7 TORQUE CONVERTER CLUTCH, STOP LAMPS SWITCH (BRAKE PEDAL SUPPORT BRACKET) TURN TURN B/U FUSE 5 TURN LEFT TURN RIGHT TURN SIGNAL FLASHER TURN SIGNAL SWITCH WHT WIRE WINDSHIELD WIPER MOTOR BREAKOUT) YEL WIRE

2-3 SHIFT SOL CTRL ANTI-LOCK BRAKE SYSTEM BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CAM POSIT SENS RTN FUEL LEV PPL CAMSHAFT POSITION (CMP) SENSOR (INTERNAL TO DISTRIBUTOR) CKP DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE GRY WIRE HALL EFFECT SENSOR IGN FEED KNOCK SENS SIG KNOCK SENSOR (KS) (TOP CENTER REAR OF ENGINE) LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE NCA WIRE PNK PNK PNK 2 3 4 WIRE PNK WIRE PNK/BLK WIRE PPL PPL CKP SENS RTN VSS RTN VSS SIG PPL/WHT WIRE PURGE VENT CTRL RETURN SENSOR CKP SENSOR SIGNAL TAN WIRE TAN/WHT WIRE TANK PRESSURE SENSOR (TOP OF FUEL TANK) VEHICLE SPEED OUT VEHICLE SPEED SENSOR (VSS) (LEFT SIDE OF TRANSMISSION) WHL SPD SIG, LEFT FRT CAM POSIT SENS SIG WHT DK GRN/ WIRE WHT LT BLU/ WIRE WHT LT GRN/ WIRE WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID AUTOMATIC TRANSMISSION (A/T) (IF EQUIPPED) (REAR OF ENGINE) BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ENG 1 FUSE 15 FUEL INJECTOR NO.2 FUEL INJECTOR NO.1 FUEL INJECTOR NO.3 FUEL INJECTOR NO.4 FUEL INJECTOR NO.5 FUEL INJECTOR NO.6 GRY WIRE HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE PNK PNK PNK 2 3 4 5 WIRE PNK PNK PNK 2 3 4 WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL/WHT WIRE PRESSURE CONTROL SOLENOID (PCS) RED WIRE RED/BLK WIRE REV TAN WIRE TAN/WHT WIRE TCC PWM SOLENOID TRANS FUSE 17 TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR TRANSMISSION RANGE (TR) PRESSURE SWITCH ASSEMBLY WHT WIRE YEL WIRE YEL/BLK WIRE

3 4 5 PNK PNK WIRE A/C COMPRESSOR HIGH PRESSURE CUT-OFF SWITCH (REAR OF A/C COMPRESSOR) BLK WIRE BREAKOUT) BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG BAT FUSE 10 ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) FROM ECT SENSOR BREAKOUT) FUEL GAUGE FUEL SENDER, FUEL PUMP (TOP OF FUEL TANK) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE MALFUNCTION INDICATOR LAMP MAP REF LO MASS AIR FLOW SENSOR (MAF) (MOUNTED IN FRESH AIR INTAKE, BEHIND AIR FILTER BOX) NCA WIRE ORG/ WIRE PNK 6 7 8 9 10 11 12 13 14 15 WIRE PNK PNK PNK 2 3 4 5 WIRE PNK PNK WIRE PNK WIRE PPL RED WIRE RED/BLK WIRE REF LO REF THROTTLE POSITION (TP) SENSOR (ON THROTTLE BODY, TOP OF ENGINE) SENSOR BREAKOUT) SPEEDO- METER TACHO- METER TAN WIRE TEMP WHT WIRE YEL WIRE

14 15 16 PPL PPL 2-3 SHIFT SOL CTRL ANTI-LOCK BRAKE SYSTEM BLK WIRE BLU/WHT WIRE BRN WIRE BRN/WHT WIRE CAM POSIT SENS RTN FUEL LEV SIGNAL PPL CAM POSIT SENS SIG CAMSHAFT POSITION (CMP) SENSOR (INTERNAL TO DISTRIBUTOR) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/ WHT WIRE DK GRN/WHT WIRE FUEL TANK PRESSURE SENSOR (AT FUEL TANK) GRY WIRE HALL EFFECT SENSOR HALL EFFECT SENSOR PNK WIRE IDLE AIR CONTROL (IAC) VALVE KNOCK SENS SIG KNOCK SENSOR (KS) (LOWER RIGHT SIDE OF ENGINE) LT BLU/ BLK WIRE LT BLU/ WHT WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WHT/ WIRE LT GRN WIRE LT GRN/BLK WIRE LT GRN/WHT WIRE MAP SENSOR IN IAT SENS SIG ECT SENSOR IN THROTTLE POSIT SENS TANK PRESSURE NCA WIRE PNK PNK 1 2 WIRE PNK PNK 30 31 WIRE PNK WIRE PNK/BLK WIRE PPL PPL CKP SENS RTN VSS RTN VSS SIG PPL PPL PPL/WHT WIRE PURGE VENT RED/BLK WIRE TAN WIRE TAN/ WHT WIRE TAN/WHT WIRE VEHICLE SPEED OUT VEHICLE SPEED SENSOR (VSS) (LEFT SIDE OF TRANSMISSION) WHT PPL/ WIRE WHT WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOLENOID 14 15 16 PPL PPL 2-3 SHIFT SOLENOID AUTOMATIC TRANSMISSION (A/T) (IF EQUIPPED) (REAR OF ENGINE) BLK WIRE BLU WIRE BLU/WHT WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE 12 ENG 1 FUSE 15 EXHAUST GAS RECIRCULATION (EGR) VALVE (TOP FRONT OF ENGINE) FUEL INJECTOR 1 FUEL INJECTOR 2 FUEL INJECTOR 3 FUEL INJECTOR 4 FUEL INJECTOR 5 FUEL INJECTOR 6 FUEL INJECTOR 7 FUEL INJECTOR 8 GRY WIRE HOT IN RUN, START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE PNK 5 6 WIRE PNK PNK 1 2 WIRE PNK PNK 30 31 WIRE PNK PNK PNK PNK 1 2 3 4 WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL 8 9 10 11 12 13 14 15 16 17 PPL/WHT WIRE PRESSURE CONTROL SOLENOID (PCS) RED WIRE RED/BLK WIRE REV TAN WIRE TAN/WHT WIRE TCC PWM SOLENOID TRANSMISSION FLUID TEMPERATURE SENSOR TRANSMISSION RANGE (TR) PRESSURE SWITCH ASSEMBLY WHT PPL/ WIRE WHT TAN/ WIRE WHT WIRE YEL WIRE YEL/BLK WIRE

"SERV THROTTLE SOON" IND A/C ENABLE GROUND GROUND 451 451 A/C SYSTEM A/T M/T ANTILOCK BRAKES SYSTEM BATTERY BATTERY WASTEGATE SOL CTRL BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE CALIFORNIA CALIFORNIA DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ESO CTRL FUSIBLE LINK FUSIBLE LINK (22 GA-RUST) FUSIBLE LINKS GLOW PLUG CONTROLLER (LEFT REAR OF ENG, NEAR FIREWALL) GRD IGNITION GLOW PLUG SIG RLY CTRL PNK WIRE HOT AT ALL TIMES LEFT BANK GLOW PLUGS LT BLU WIRE LT GRN WIRE NCA WIRE ORG/ WIRE PNK IGNITION RLY CTRL GRD BATTERY GLOW PLUG OUT WIRE PNK PNK 439 439 IGNITION IGNITION BATTERY MIL IND CTRL WIRE PNK PNK WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (LEFT SIDE OF DRIVER'S ISLAND ON RELAY BRACKET) PPL PPL GLOW PLUG OUT GLOW PLUG OUT GLOW PLUG OUT GLOW PLUG OUT RED WIRE RIGHT BANK GLOW PLUGS TAN WIRE WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

"WAIT TO START" GLOW PLUGS 1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID A/T AUTOMATIC TRANSMISSION (REAR OF ENGINE) BLK WIRE BLK/WHT WIRE BRN WIRE DK BLU WIRE DK GRN WIRE ECM 1 FUSE 12 ECM-BAT FUSE 6 FUEL INJECTION PUMP SHUT-OFF SOLENOID (AT FUEL INJECTION PUMP) FUEL LIFT PUMP (ON INSIDE RIGHT FRAME RAIL) FUEL PUMP RELAY (ON ENGINE FIREWALL BRACKET, UNDER BATTERY JUNCTION BLOCK) GAUGES FUSE 8 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE M/T NCA WIRE ORN/ PNK 3 4 5 6 7 8 WIRE PNK WIRE PRESSURE CONTROL SOLENOID RED WIRE RED/BLK WIRE SERVICE TRANS SPEEDO- METER TCC PWM SOLENOID TRANS FUSE 17 TRANSMISSION FLUID TEMPERATURE (TFT) SENSOR TRANSMISSION RANGE (TR) PRESSURE SWITCH ASSEMBLY WATER IN FUEL WHT WIRE YEL WIRE YEL/BLK WIRE

A/T A/T M/T BATTERY FEED BATTERY JUNCTION BLOCK (ON LEFT REAR OF ENG COMPT) BLK WIRE BLU WIRE BRN WIRE CRANK FUSE (UPPER RIGHT SIDE OF STEERING COLUMN SUPPORT) DK BLU WIRE ENG 1 FUSE 15 FUEL HEATER (REAR OF INTAKE MANIFOLD, PART OF FUEL/ WATER SEPARATOR) FUEL INJECTION PUMP COLD ADVANCE SOLENOID (AT FUEL INJECTION PUMP) FUSIBLE LINK FUSIBLE LINK (12 GA- FUSIBLE LINK (16 GA- FUSIBLE LINK (22 GA-RUST) FUSIBLE LINKS GLOW PLUG CONTROLLER (LEFT REAR OF ENG, NEAR FIREWALL) GLOW PLUG CTRL GLOW PLUG OUT GROUND HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (BEHIND DASH PANEL) (BODY BUILDER INSTALLED) IDLE SPEED CONTROL ACTUATOR SOLENOID (ON BRACKET ON FRONT FUEL INJECTION PUMP) IGN FEED IND LAMP OUT GROUND IGNITION SWITCH LEFT BANK GLOW PLUGS LOCK OFF LT GRN/BLK WIRE NOT USED STARTER FEED ORG/ WIRE PNK IGN FEED WIRE PNK WIRE PPL PPL PPL PPL S STUD RED WIRE RIGHT BANK GLOW PLUGS RUN WIRE 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 INDICATOR SENSOR WHT WIRE YEL WIRE YEL/BLK WIRE