GMC Forward Control P3500 (1985-1999) org/ Wiring diagrams

A/C COMPRESSOR CLUTCH RELAY (ENGINE FIREWALL RELAY BRACKET) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF A/C COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (A/C ACCUMULATOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (ON A/C ACCUMULATOR) A/C ENABLE A/C GROUND BLK WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK LT BLU WIRE ORG/ WIRE PNK WIRE VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) A/C REQUEST WHT WIRE

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

A/C COMPRESSOR CLUTCH RELAY (ENGINE FIREWALL RELAY BRACKET) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF A/C COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (A/C ACCUMULATOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (ON A/C ACCUMULATOR) A/C ENABLE A/C GROUND BLK WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK LT BLU WIRE ORG/ WIRE PNK WIRE VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) A/C REQUEST WHT WIRE

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

A/C COMPRESSOR CONTROL RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (IN HIGH PRESSURE LINE) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (REAR OF A/C COMPRESSOR) A/C ENABLE BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN I/P FUSE BLOCK ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (LEFT SIDE OF DRIVER'S ISLAND) A/C REQUEST WHT WIRE

A/C COMPRESSOR CLUTCH RELAY (ENGINE FIREWALL RELAY BRACKET) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF A/C COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (ON A/C ACCUMULATOR) BLK WIRE DIODE A/C COMPRESSOR CLUTCH DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK ORG/ WIRE VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) W/ VCM W/O VCM WHT (OR WIRE WHT WIRE

A/C COMPRESSOR CLUTCH RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF A/C COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (A/C ACCUMULATOR) A/C ENABLE A/C GROUND A/C REQUEST BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE DK GRN/WHT WIRE ENG-BAT FUSE GAUGES FUSE GRN WIRE HOT AT ALL TIMES HOT IN RUN I/P FUSE BLOCK ORG/ WIRE PNK WIRE VEHICLE CONTROL MODULE (CENTER FRONT OF ENGINE COMPT) WHT WIRE

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

A/C COMPRESSOR CLUTCH RELAY (RIGHT SIDE OF DRIVER'S ISLAND) A/C COMPRESSOR HIGH PRESSURE CUTOFF SWITCH (REAR OF COMPRESSOR) A/C COMPRESSOR REFRIGERANT PRESSURE SWITCH (REAR OF COMPRESSOR) BLK WIRE BRN WIRE DIODE A/C COMPRESSOR CLUTCH DK GRN WIRE ENG-BAT FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES I/P FUSE BOX ORG/ WIRE

BLK WIRE BLU WIRE BREAKOUT FOR HEADLAMP SWITCH) BULB TEST DAYTIME RUNNING LAMPS MODULE (ATTACHED TO I/P HARNESS AT STEERING COLUMN) DAYTIME RUNNING LAMPS RELAY (ON MAIN SUPPORT BRACKET AT DRIVER'S ISLAND) DAYTIME RUNNING LAMPS RELAY 2 DIODE NETWORK DK BLU WIRE DK GRN/WHT WIRE DRL INDICATOR FOR LEFT HEADLAMP) FUSIBLE LINK (16 GA- GAUGES FUSE GRN WIRE HEAD- LAMP DIMMER SWITCH HEADLAMPS SWITCH HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LEFT HEAD- LAMP LEFT HIGH BEAM HEAD- LAMP LO HI LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PARK BRAKE IN FOG LAMPS PARK BRAKE INDICATOR SWITCH (ON PARK BRAKE) PARK HEAD OFF PNK IGNITION LAMP FEED HI BM FEED HI BM INDICATOR RELAY OUT GROUND WIRE PNK WIRE RED WIRE RIGHT HEAD- LAMP RIGHT HIGH BEAM HEAD- LAMP RUN WIRE TAN WIRE WHT WIRE YEL WIRE