GMC Pickup C2500 (1985-2000) blk/wht Wiring diagrams

1-2 SHIFT SOLENOID 2-3 SHIFT SOLENOID 29 30 VSS LO (GROUND) VSS HI (SIGNAL) ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CRUISE CONTROL DK BLU WIRE ECM 1 FUSE ECM-B FUSE ELECTRONIC BRAKE CONTROL MODULE ENGINE CONTROLS ENGINE COOLANT TEMPERATURE SENSOR (TOP RIGHT FRONT OF ENGINE) FLUID TEMP SENSOR FRONT WHEEL LOCK FUEL INJECTORS, IGNITION CONTROL MOUDULE, IGNITION COIL FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GRY WIRE GRY/BLK WIRE HI LO HOT AT ALL TIMES HOT IN HOT IN OFF, RUN OR START HOT IN RUN OR START HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DSAH) GAUGES FUSE 4 I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) INLINE GENDER ADAPTOR INSTRUMENT CLUSTER LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MALFUNCTION INDICATOR LAMP ORG/ WIRE PNK PNK WIRE PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL SOLENOID RED WIRE RED/BLK WIRE REV, LO RUN WIRE TAN WIRE TCC PWM SOLENOID TCC/ABS/ CRUISE SWITCH THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANSFER CASE CIRCUIT TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT SIDE OF YEL WIRE YEL/BLK WIRE

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE RECIRC DOOR SIGNAL IGNITION A/C COMPRESSOR CLUTCH A/C COMPRESSOR CLUTCH RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT RECIRCULATION DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD BLOWER FUSE 3 FUSE BLOCK HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE BLOCK VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WHT WIRE YEL WIRE

39 (OR 1020) 7.4L VIN J ONLY 900 419 507 389 12 5 15 4 FUEL RET MIL IND UPSHIFT IND SPEEDO ACCY ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM ANTI-THEFT SYSTEM BAT IND HI BEAM IND BLK WIRE BLK/WHT WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (ON UNDERSIDE OF ELECTRONIC BRAKE CONTROL MODULE) BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER CONVENIENCE CENTER DAYTIME RUNNING LAMPS IND AIR BAG IND DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ELECTRONIC BRAKE CONTROL MODULE (EBCM) (ON LEFT SIDE OF ENGINE COMPT) ENGINE CONTROLS SYSTEM (FUEL PUMP BALANCE RELAY) FUEL GAUGE FUEL PUMP BALANCE MODULE (INSIDE LEFT SIDE OF FRAME RAIL) FUEL PUMP, SENDER (IN FUEL TANK) GRN WIRE GRY WIRE HEADLIGHTS SYSTEM HOT IN RUN OR START I/P FUSE BLOCK GAUGES FUSE 4 HOT IN RUN, BULB TEST OR START IGN IGN E MINI FUSE IGN SW BRAKE IND BRAKE PSI PK BRAKE 33 33 IGNITION COIL (TOP LEFT REAR OF ENGINE) IGNITION SWITCH ILLUMINATION INSTRUMENT CLUSTER LED DIMMING LEFT TURN IND LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T A/T PNK WIRE MALFUNC- TION INDICATOR LAMP NCA WIRE PARITY PRNDL PARK BRAKE SWITCH (ON PARK BRAKE PEDAL BRACKET) PNK WIRE PPL PPL 9 29 30 FUEL VSS VSS PPL/WHT WIRE PRNDL PRNDL A PRNDL B PRNDL C RIGHT TURN IND RUN WIRE SAFETY BELT IND SECONDARY FUEL GAUGE SENDER (IN REAR FUEL TANK) SECURITY IND SENS RTRN FUEL IN SERVICE ENGINE SOON SINGLE FUEL TANK DUAL FUEL TANKS SPEEDOMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/WHT WIRE TEMP GAUGE OIL GAUGE TRANS FUSE 20 TRANSMISSION RANGE SWITCH TWISTED PAIR UNDERHOOD FUSE BLOCK UPSHIFT IND (M/T ONLY) VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT SIDE OF TRANSMISSION, LEFT SIDE OF TRAN- VEHICLE SPEED SENSOR (VSS) ADAPTER VOLTMETER WARNING SYSTEMS WHT WIRE YEL WIRE

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE RECIRC DOOR SIGNAL IGNITION A/C COMPRESSOR CLUTCH A/C COMPRESSOR CLUTCH RELAY (IN UNDERHOOD FUSE/RELAY CENTER) A/C COMPRESSOR CYCLING SWITCH (IN LOW PRESSURE LINE, ON ACCUMULATOR) A/C CTRL A/C HIGH PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C LOW PRESSURE CUTOUT SWITCH (ON A/C COMPRESSOR) A/C REQ AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (EXC 4.3L) (IN UNDERHOOD FUSE/RELAY CENTER) BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLK/WHT WIRE BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DIODE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FRONT RECIRCULATION DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD BLOWER FUSE 3 FUSE BLOCK HOT IN RUN HOT IN RUN OR START HTR A/C FUSE 12 HVAC CONTROL MODULE IGN E FUSE A/C COMP FUSE LT BLU WIRE LT GRN WIRE OFF LO ORG/ WIRE PNK WIRE PPL REAR DEFOGGER SYSTEM RED WIRE SW SIG SW SIG RELAY CTRL TAN WIRE UNDERHOOD FUSE BLOCK VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WHT WIRE YEL 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 AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU/WHT WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (ON BRAKE PEDAL BRACKET) BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE FRONT WHEEL LOCK FUEL INJECTORS, IGNITION CONTROL MOUDULE, IGNITION COIL FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HEADLAMP, PANEL DIMMER SWITCH PNK WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION IN INSTRUMENT CLUSTER LEFT REAR SIDE LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE MAF SENSOR, HEATED OXYGEN SENSORS MALFUNCTION INDICATOR LAMP MIL CONTROL ORG/ WIRE PCM GROUND PCS SOL HI OUT PCS SOL LO OUT PNK WIRE PPL PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) PPL/WHT WIRE PRESS CTRL HI SOLENOID LO RANGE SIGNAL "A" RANGE SIGNAL "B" RANGE SIGNAL "C" RED WIRE RED/BLK WIRE SENSOR GROUND SENSOR RETURN TAN WIRE TCC PWM SOL TCC PWM SOLENOID THROTTLE POSITION SENSOR (MOUNTED TO SIDE OF THROTTLE BODY) TP SENS INPUT TRANS FLUID TEMP SENSOR TRANS FUSE 20 TRANS RANGE PRESSURE SWITCH ASSEMBLY TRANS RANGE SWITCHES TRANS TEMP SIG IN TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO YEL WIRE YEL/BLK WIRE

BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (DLC) (LEFT SIDE OF DASH) DK GRN WIRE ELECTRONIC POWER STEERING SYSTEM ENGINE CONTROLS SYSTEM EVO SOL FEED EVO SOL OUT EVO/PASSLOCK MODULE (NEAR DASH AUXILIARY STORAGE COMPARTMENT) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PASSLOCK SENSOR (IN STEERING COLUMN, NEAR LOCK CYLINDER) PNK PPL WIRE PNK WIRE PPL RED WIRE RED/WHT WIRE RESISTOR 10 OHMS SEC/STRG FUSE 21 SECURITY INDICATOR SENSOR PASSLOCK GRD SIGNAL STEERING HANDWHEEL SPEED SENSOR (SENSOR GROUND) WHT WIRE YEL WIRE

AUXILIARY HEATER- A/C LOGIC MODULE BALANCE FUEL PUMP BLK WIRE BLK/WHT WIRE CENTER HIGH MOUNT STOPLAMP CHASSIS CAB, HEAVY DUTY DOOR CONTACT BUTTON DOOR LOCK CONTROL MODULE EXCEPT CHASSIS CAB, HEAVY DUTY FRONT AUXILIARY HEATER-A/C CONTROL MODULE FRONT REAR DOME DOME LAMP LAMP FUEL LIFT PUMP INFLATABLE RESTRAINT FRONT END SENSOR INFLATABLE RESTRAINT SENSING AND DIAGNOSTIC MODULE LEFT CARGO DOOR DEFOGGER GRID LEFT LEFT REAR FRONT CLEARANCE CLEARANCE LAMP LAMP LEFT REAR FENDER LEFT REAR TAIL, STOP, LICENSE, TURN, BACKUP LAMPS LEFT REAR TAIL, STOP, TURN, LEFT BACKUP LICENSE LAMP LAMPS LEFT TAIL, STOP, LEFT TURN, LICENSE BACKUP LAMPS LAMP OVERHEAD CONSOLE LAMPS PICKUP W/ DUAL REAR WHEELS REAR AUXILIARY HEATER-A/C CONTROL MODULE REAR AUXILIARY MODE DOOR MOTOR REAR AUXILIARY TEMP DOOR MOTOR REAR BLOWER MOTOR REAR LIFTGATE WINDOW DEFOGGER GRID REAR WIPER MOTOR MODULE RIGHT CARGO DOOR DEFOGGER GRID RIGHT ENDGATE LICENSE MARKER LAMP LAMPS RIGHT LICENSE LAMP RIGHT REAR DOOR JAMB SWITCH RIGHT REAR FENDER RIGHT REAR TAIL, STOP, LICENSE, TURN, BACKUP LAMPS RIGHT REAR TAIL, STOP, TURN, BACKUP LAMPS RIGHT RIGHT REAR FRONT CLEARANCE CLEARANCE LAMP LAMP RIGHT TAIL, STOP, TURN, BACKUP LAMPS SUBURBAN/ UTILITY TRAILER GROUND (TAPED BACK) UTILITY ONLY W/ DUAL TANKS WHT WIRE

1134 1134 39 10 10 PARK BRAKE SIG IND BULB CHK IGNITION LAMP FEED PNK WIRE 33 33 BRAKE IND CTRL BRAKE WARN IN 592 592 150 DRL RELAY CTRL BLK WIRE BLK/WHT WIRE BRN WIRE BULB TEST CONVENIENCE CENTER (UNDER LEFT SIDE OF DASH) DAYTIME RUNNING LAMP MODULE (BEHIND LEFT SIDE OF DASH) DAYTIME RUNNING LAMPS RELAY DIODE 203 DRL INDICATOR DRL-FOG FUSE 15 FOG LAMP RELAY FOG LAMP SWITCH GAUGES FUSE 4 GRN WIRE GROUND GRY WIRE HEAD OFF PARK HEAD- LAMP DIMMER SWITCH HEADLAMP, PANEL DIMMER SWITCH HIGH BEAM INDICATOR HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT SIDE OF DASH, IGNITION SWITCH ILLUM LAMP INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM (BRAKE WARNING INDICATOR) LEFT FOG LAMP LEFT HEAD- LAMP RIGHT HEAD- LAMP LIGHTING FUSE 8 LOCK OFF LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE OFF ON INDICATOR ORG/ WIRE PARK BRAKE WARNING SWITCH PK LPS FUSE 9 PNK WIRE PPL RED WIRE RIGHT FOG LAMP RUN WIRE TAN WIRE TAN/WHT WIRE UNDERHOOD FUSE BLOCK (LEFT REAR OF ENGINE COMPT) W/ FOG LAMPS WHT WIRE YEL WIRE

BATT B BELT SWITCH BREAKOUT) BLK WIRE BLK/WHT WIRE CIG LTR FUSE 13 CONVENIENCE CENTER (LEFT SIDE OF DASH) DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) DOOR LOCK RELAY (UNDER CENTER OF DASH, NEAR REMOTE CONTROL DOOR LOCK RECEIVER) DRIVER DR UNLK UNLOCK OUT HORN SIGNAL GAUGES FUSE 4 GROUND GRY WIRE HORNS SYSTEM HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT SIDE OF DASH, INTERIOR LAMPS SYSTEM LEFT DOOR LOCK SWITCH LEFT FRONT DOOR LOCK ACTUATOR LOCK LOCK OUT DOME LAMPS LT BLU WIRE ORG/ WIRE PASS DRS UNLK PNK IGNITION DOME LMP OFF PROGRAM SIG WIRE PNK WIRE PWR ACCY C.B. REMOTE CONTROL DOOR LOCK RECEIVER (UNDER CENTER OF DASH PANEL) RIGHT DOOR LOCK SWITCH RIGHT FRONT DOOR LOCK ACTUATOR SEAT BELT SWITCH BREAKOUT) TAN WIRE UNLOCK W/O POWER WINDOWS W/ POWER WINDOWS WHT WIRE

BLK/WHT WIRE BRN WIRE CAPACITOR DK GRN/WHT WIRE ELECTRONIC POWER STEERING SYSTEM ENGINE CONTROLS SYSTEM EVO SOL FD EVO SOL OUT EVO/PASSLOCK MODULE (UNDER CENTER OF DASH) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU WIRE NCA WIRE ORG/ WIRE ORG/BLK WIRE PASSLOCK SENSOR (INTERNAL TO STEERING COLUMN) PASSLOCK SIGNAL PNK PPL WIRE PNK WIRE PPL DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH) RED WIRE RED/WHT WIRE RESISTOR 10 OHMS SECURITY FUSE 21 SECURITY INDICATOR SENSOR GRD STEERING HANDWHEEL SPEED SENSOR (SENSOR GROUND) WHT WIRE YEL WIRE