GMC Pickup C2500 (1985-2000) dk blu Wiring diagrams

419 456 389 5 15 4 MIL IND UPSHIFT IND SPEEDO ACCY BULB TEST LOCK OFF ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM BAT IND BLK WIRE BLK/WHT WIRE BRAKE IND BRAKE PRESSURE WARNING SWITCH (ON REAR OF EBCM CASTING) BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER DAYTIME RUNNING LAMPS IND AIR BAG IND DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF DASH, TAPED TO DASH HARNESS) DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM (FUEL PUMP BALANCE RELAY) ENGINE COOLANT TEMPERATURE SENDER (LEFT CYLINDER HEAD) FUEL GAUGE FUEL PUMP BALANCE MODULE (INSIDE LEFT SIDE FRAME RAIL) FUEL PUMP, SENDER (IN FRONT FUEL TANK) FUEL PUMP, SENDER (IN FUEL TANK) GRN WIRE GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (LEFT END OF DASH) GAUGES FUSE 4 IGN IGN E MINI FUSE IGN SW BRAKE IND BRAKE PSI PK BRAKE 33 33 IGNITION COIL (RIGHT REAR OF ENGINE) IGNITION SWITCH ILLUM ILLUMINATION INSTRUMENT CLUSTER LED DIMMING LEFT TURN IND LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE M/T A/T PNK WIRE OIL GAUGE PARITY PRNDL 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 GAGE SENDER (IN REAR FUEL TANK) SENS RTRN FUEL IN SERVICE ENGINE SOON IND SINGLE FUEL TANK DUAL FUEL TANKS STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TEMP GAUGE TRANS FUSE 20 TRANSMISSION RANGE SELECTOR (LEFT SIDE OF TRANSMISSION) TWISTED PAIR UNDERHOOD FUSE-RELAY CENTER UPSHIFT IND (M/T ONLY) VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT REAR OF TRANSMISSION OR TRANSFER CASE) VEHICLE SPEED SENSOR (VSS) ADAPTER VOLTMETER SPEEDOMETER WARNING SYSTEMS WHT TAN/ WIRE WHT WIRE YEL WIRE

1-2 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID 3-2 DOWNSHIFT SOL AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU WIRE BRAKE FUSE 18 BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DASH FUSE BLOCK DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP RIGHT FRONT OF ENGINE) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN OFF, RUN OR START HOT IN RUN HOT IN RUN OR START IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE 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 PNK WIRE 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 STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC PWM SOLENOID TCC SOL TCC 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 CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO WHT WIRE YEL WIRE YEL/BLK 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 SHIFT SOL 1-2 SHIFT SOLENOID 2-3 SHIFT SOL 2-3 SHIFT SOLENOID 3-2 CTRL SOLENOID 3-2 DOWNSHIFT SOL AUTOMATIC TRANSMISSION BATTERY IN BLK WIRE BLK/WHT WIRE BLU WIRE BRAKE FUSE 18 BRAKE SWITCH INPUT BRN WIRE BRN/WHT WIRE DASH FUSE BLOCK DATA CLASS II DK BLU WIRE ECM 1 FUSE ECM-B FUSE ECT SENS INPUT ELECTRONIC BRAKE CONTROL MODULE ENG 1 FUSE ENGINE COOLANT TEMP SENSOR (TOP RIGHT FRONT OF ENGINE) FRONT WHEEL LOCK FUEL PUMP, OIL PRESS SWITCH/ SENDER, FUEL PUMP RELAY GAUGES FUSE 4 GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN OFF, RUN OR START HOT IN RUN HOT IN RUN OR START IGNITION IN INSTRUMENT CLUSTER LT BLU WIRE 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 PNK WIRE 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 STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) TAN WIRE TAN/BLK WIRE TCC PWM SOL TCC PWM SOLENOID TCC SOL TCC 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 CIRCUIT PNK WIRE TRANSFER CASE, AXLE SWITCHES UNDERHOOD FUSE/RELAY CENTER VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR VEHICLE SPEED SENSOR ADAPTOR VSS HI VSS LO WHT WIRE YEL WIRE YEL/BLK WIRE

39 (OR 1020) AIR BAG IND ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM ANTI-THEFT SYSTEM BLK WIRE BLK/WHT WIRE BRAKE IND BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER DAYTIME RUNNING LAMPS IND DIMMING LED DK BLU WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM FUEL GAUGE FUEL PUMP/ OIL PRESSURE SWITCH, SENDER (UNDER INTAKE MANIFOLD, CENTER OF ENGINE) GENERATOR GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND IGN ILLUMINATION IND INSTRUMENT CLUSTER LOW COOLANT IND LOW COOLANT LEVEL INDICATOR MODULE (BEHIND CENTER OF DASH) LOW COOLANT LEVEL SWITCH (IN COOLANT RESERVOIR, RIGHT SIDE OF ENGINE COMPT) LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE OIL PRESS PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE PRNDL PRNDL A PRNDL B PRNDL C PRNDL PARITY RIGHT TURN IND LEFT TURN IND SAFETY BELT IND SECURITY IND SERVICE ENGINE SOON IND SERVICE THROTTLE SOON IND SOLID STATE SPEED- OMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/WHT WIRE TEMP GAUGE TRANSMISSION RANGE SWITCH (LEFT SIDE OF TRANSMISSION) VOLT- METER WAIT TO BAT IND WARNING SYSTEMS WATER IN FUEL IND WATER IN-FUEL SENSOR (ON FUEL FILTER/ MANAGER) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

AIR BAG IND ANTI- LOCK BRAKES IND ANTI-LOCK BRAKES SYSTEM BAT IND WAIT TO BLK WIRE BLK/WHT WIRE BRAKE IND BRN WIRE BRN/WHT WIRE CHECK GAUGES IND CHECK GAUGES LAMP DRIVER DAYTIME RUNNING LAMPS IND DK BLU WIRE DK GRN WIRE ENGINE CONTROLS SYSTEM FUEL GAUGE GENERATOR GRY WIRE HEADLIGHTS SYSTEM HI-BEAM IND IGN ILLUM ILLUMINATION IND INSTRUMENT CLUSTER LED DIMMING LEFT TURN IND RIGHT TURN IND LOW COOLANT IND LOW COOLANT LEVEL INDICATOR MODULE (BEHIND CENTER OF DASH) LOW COOLANT LEVEL SENSOR (IN COOLANT RESERVOIR, RIGHT SIDE OF ENGINE COMPT) LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE OIL PRESS OIL PRESSURE SWITCH, SENDER (UNDER INTAKE MANIFOLD, CENTER OF ENGINE) PARITY PRNDL PNK PNK WIRE PNK PPL WIRE PNK WIRE PPL PPL/WHT WIRE PRNDL PRNDL A PRNDL B PRNDL C SAFETY BELT IND SERVICE ENGINE SOON IND SERVICE THROTTLE SOON IND SOLID STATE SPEED- OMETER STARTING/CHARGING SYSTEM SUPPLEMENTAL RESTRAINTS SYSTEM TACH TAN WIRE TAN/WHT WIRE TEMP GAUGE TRANSMISSION RANGE SELECTOR (LEFT SIDE OF TRANSMISSION) UP- SHIFT IND (M/T) VOLT- METER WARNING SYSTEM WATER IN FUEL IND WATER-IN FUEL SENSOR (TOP REAR OF ENGINE) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

33 (OR 1134) 592 592 150 DRL RELAY CTRL BLK WIRE BLK/WHT WIRE BRN WIRE BULB CHECK 1317 39 10 10 FOG LAMPS IGNITION LAMP FEED PNK WIRE DIODE 203 (I/P HARNESS, RIGHT SIDE OF STEERING COLUMN) DK BLU WIRE DK GRN/WHT WIRE DRL-FOG FUSE 15 FOG LAMP RELAY (UNDER LEFT END OF I/P) FOG LAMP SWITCH GAGES FUSE 4 GRN WIRE GROUND GRY WIRE HEAD HEAD OFF OFF PARK PARK HEAD- LAMP DIMMER SWITCH HEADLAMP, PANEL DIMMER SWITCH HI LO HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK IGNITION SWITCH ILLUM LAMP INSTRUMENT CLUSTER HI BEAM INDI- CATOR DRL INDI- CATOR INSTRUMENT CLUSTER SYSTEM LEFT FOG LAMP RIGHT FOG LAMP LEFT HEAD- LAMP LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE NCA WIRE OFF ON INDICATOR ORG/ WIRE PARK BRAKE WARNING SWITCH (ON PARK BRAKE) PNK WIRE PPL PPL PPL RIGHT HEAD- LAMP TAN WIRE TAN/WHT WIRE W/ FOG LAMPS YEL WIRE

27 28 29 30 31 PPL 5 VOLT REF ACCELERATOR PEDAL POSITION (APP) MODULE (PART OF ACCELERATOR PEDAL) BLK WIRE BLU WIRE BRAKE FUSE 18 BRAKE SWITCH ASSEMBLY (AT REAR OF BRAKE PEDAL SUPPORT BRACKET) BRN WIRE BRN/WHT WIRE CLUTCH PEDAL POSITION (CPP) SWITCH (M/T ONLY) (TOP OF CLUTCH PEDAL) CMP SIG DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM 1 FUSE ELECTRONIC BRAKE CONTROL MODULE (ON LEFT SIDE OF ENGINE COMPT) GRN WIRE GRY WIRE HIGH RES SIG HOT AT ALL TIMES HOT IN HOT IN RUN OR START I/P FUSE BLOCK INJECTION TIMING STEPPER MOTOR (TOP RIGHT FRONT OF ENGINE) LT BLU WIRE LT GRN WIRE LT PPL NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 WIRE PNK PNK 8 9 WIRE PNK PNK PNK WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE POWER DISTRIBUTION SYSTEM PPL PPL (OR BRN/WHT) WIRE RED WIRE RED/BLK WIRE RUN WIRE SENS GRD STOP/HAZ FUSE 1 TAN WIRE TAN/BLK WIRE TRANS FUSE 20 UNDERHOOD FUSE-RELAY CENTER WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

"GLOW PLUGS" INDICATOR BLK WIRE BLK/WHT WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-B FUSE FUEL LIFT PUMP (INSIDE LEFT FRAME RAIL, BELOW DRIVER'S DOOR) FUEL PUMP PRIME CONNECTOR FUEL PUMP RELAY (IN UNDERHOOD FUSE-RELAY CENTER) GAUGES FUSE 4 GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM INSTRUMENT CLUSTER SYSTEM (FUEL PUMP BALANCE RELAY) LT GRN WIRE ORG/ WIRE PNK PNK 8 9 WIRE PNK PNK PNK WIRE PNK WIRE RED WIRE SERVICE ENGINE SOON INDICATOR SERVICE THROTTLE SOON INDICATOR TAN WIRE UNDERHOOD FUSE-RELAY CENTER VEHICLE SPEED INPUT W/DUAL TANKS W/O DUAL TANKS WAIT TO WATER IN FUEL INDICATOR WATER IN-FUEL SENSOR (TOP CENTER REAR OF ENGINE) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

"SERV ENG SOON" IND ENGINE SHUTOFF SOL OUT EGR SOL OUTPUT "SERV THROTTLE SOON" IND EGR VALVE SOL PUTPUT A/C ENABLE PCM GND PCM GND A/C SYSTEM BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN/WHT WIRE ELECTRONIC BRAKE BRAKE CONTROL MODULE (EBCM) (ON LEFT SIDE OF ENGINE COMPT) ENG-I FUSE EXHAUST GAS RECIRCULATION (EGR) VENT SOLENOID (TOP LEFT REAR OF ENGINE) EXHAUST GAS RECIRCULATION EGR SOLENOID (TOP LEFT REAR OF ENGINE) FUEL HEATER (TOP REAR OF ENGINE) FUEL SOL MODULE (5 VREF) FUSIBLE LINK FUSIBLE LINKS GLOW GLOW PLUG 3 PLUG 5 GLOW PLUG 1 GLOW PLUG 2 GLOW PLUG 4 GLOW PLUG 6 GLOW PLUG 7 GLOW PLUG 8 GLOW PLUG OUTPUT GLOW PLUG RELAY (TOP LEFT REAR OF ENGINE) GRD GROUND GRY WIRE HOT AT ALL TIMES FUSIBLE LINK HOT IN RUN OR START LT GRN WIRE ORG/ WIRE PNK IGN WIRE PNK PNK 439 439 IGNITION IGNITION WIRE PNK PNK PNK WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (BEHIND RIGHT SIDE OF DASH, NEAR BLOWER MOTOR) PPL RED WIRE RELAY CTRL SIGNAL TAN WIRE TAN/WHT WIRE UNDERHOOD FUSE-RELAY CENTER WASTEGATE SOL ENGINE SHUTOFF SOL OUT WASTEGATE SOLENOID (TOP LEFT REAR OF ENGINE) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE