GMC Pickup C2500 (1985-2000) blk Wiring diagrams

BACKUP LAMPS SIGNAL (TRAILER TOW PACKAGE) (WIRE CUT AND TAPED TO HARNESS) BLK WIRE FROM LICENSE LAMP BREAKOUT) HOT IN RUN OR START I/P FUSE BLOCK LEFT BACKUP LAMP LT GRN WIRE MIRRORS SYSTEM PARK/NEUTRAL POSITION SWITCH (LEFT CENTER OF TRANSMISSION) PNK A/T WIRE PNK M/T WIRE PNK WIRE RIGHT BACKUP LAMP TURN B/U FUSE 16

A/C REQUEST SIGNAL AIR CONDITIONING SYSTEM AIR INLET VLV MTR CTLR AUTOMATIC AUTOMATIC TRANSFER CASE SHIFT CONTROLLER BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CLUTCH PEDAL POSITION (CPP) SWITCH (AT TOP OF CLUTCH PEDAL BRACKET) CPP SW INPUT FOUR WHL DR SIG LO CRUISE CTRL SIG ENG 23 24 CRUISE CONTROL MODULE (LEFT REAR OF ENGINE COMPT, ON FIREWALL) DATA LINK CONNECTOR (UNDER LEFT SIDE OF DASH, LEFT SIDE OF STEERING COLUMN) DISTRIBUTOR DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC VARIABLE ORIFICE/ PASSLOCK CONTROL MODULE (CENTER OF DASH) FORCE MOTOR FEED TRANS INPUT SPEED RTN TRANS INPUT SPEED SIG EST OUTPUT SIG FORCE MOTOR RETURN GROUND GROUND SENSOR GROUND FUEL LEVEL INPUT SWITCH SIGNAL FUEL PUMP PRIME CONNECTOR (LEFT REAR OF ENG COMPT) FUEL PUMP RELAY FUEL PUMP RLY CTRL 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 GRN WIRE GROUND GRY WIRE GRY/BLK WIRE HIGH VOLTAGE COIL WIRE HOT AT ALL TIMES UNDERHOOD FUSE- RELAY CENTER ECMB FUSE HOT IN RUN I/P FUSE BLOCK IGN BRAKE INPUT INPUT SW INPUT IGNITION IGNITION COIL (TOP RIGHT REAR OF ENGINE) IGNITION CONTROL MODULE (RIGHT SIDE REAR OF ENGINE) IGNITION FEED IGN TIMING SIG. IGN COIL OUT IGNITION PRESSURE SWITCH INPUT PRESSURE SWITCH INPUT LT BLU/BLK WIRE LT BLU/WHT WIRE LT DK VSS SERIAL INPUT DATA SIG MANUAL OR SELECTABLE ORG/ WIRE PNK IGNITION FOUR WHL DR SIG EGR VLV GROUND WIRE PNK PNK PNK WIRE PNK WIRE PPL PPL (OR PPL A/T M/T PPL PPL PPL PPL 420 OR PPL/WHT WIRE PRESSURE SWITCH INPUT RADIO RED WIRE RED/BLK WIRE SENSOR RETURN SHIFT IND LP OUT EGR VLV FEED SPEED SENSOR SPEED STOPLAMP/ VCM SENSOR CLUTCH SIG INPUT SWITCH INPUT STOPLAMP SWITCH (TOP OF BRAKE PEDAL) SWITCH SIGNAL TAN/BLK WIRE TRANSFER CASE CONTROL MODULE (UNDER DASH ON STEERING COLUMN SUPPORT BRACKET) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE) UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VSS SIG OUT VSS SIG OUT CHECK ENG LP CTRL 389 419 WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 12 7 8 9 10 VSS SIG VSS RTN GROUND IGN VSS SIG 1226 1225 RANGE MODE SEL C RANGE MODE SEL B RANGE MODE SEL A 13 14 15 VSS HI VSS OUTPUT VSS OUTPUT 27 28 29 30 31 PPL A/C REQUEST SIG A/C SYSTEM A/T FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BRN WIRE BRN/WHT (M/T) WIRE BRN/WHT WIRE CRUISE CONTROL SYSTEM DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK PNK WIRE ECT TEMP SENS IN GRN WIRE GRY WIRE GRY/BLK WIRE INLINE GENDER ADAPTER INTAKE MAN AIR TEMP SENS APP 2 SIG GLOW PLUG RELAY FORCE MTR LOW LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT PNK WIRE LT PPL LT PPL PPL MAP SENS INPUT FORCE MTR HI NCA WIRE ORG/ WIRE ORG/BLK WIRE OTHERS PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 WIRE PNK WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (BEHIND RIGHT SIDE OF DASH, NEAR BLOWER MOTOR) PPL PPL (A/T) BRAKE SW IN BRAKE SWITCH INPUT CRUISE CTRL SW ENGAGE PPL (OR BRN/WHT) WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RADIO, EVO/ PASSLOCK CONTROL MODULE, TRANSFER CASE CONTROL MODULE RED WIRE RED/BLK WIRE SENSOR GND TAN WIRE TAN/BLK WIRE TIMING STEPPER MTR (HIGH) 3 MODE CRUISE PPL SENSOR GND SENSOR GND APP 1 SIG TIMING STEPPER MTR (LOW) TIMING STEPPER MTR (LOW) TORQUE CONVERTER CLUTCH PULSE WDTH MOD SOL TRANSMISSION SPEED INPUT TRANSMISSION TEMP INPUT TRANSMISSION TEMPERATURE SENSOR TRANSMISSIONS SYSTEM VEHICLE SPEED SENSOR (LEFT SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS VSS LO HI WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK 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 BRN WIRE BRN/WHT WIRE CLUTCH PEDAL POSITION (CPP) SWITCH (M/T ONLY) (TOP OF CLUTCH PEDAL BRACKET) CMP SIG DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK PNK WIRE ECM 1 FUSE ELECTRONIC BRAKE CONTROL MODULE (ON LEFT SIDE OF ENGINE COMPT) ENGINE SHUTOFF SOLENOID (TOP OF FUEL INJECTION PUMP) 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 OPTICAL FUEL TEMPERATURE SENSOR (ON TOP OF FUEL INJECTION PUMP) 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 PPL 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- LAMP SWITCH (ON TOP OF BRAKE PEDAL) 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 BLU WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-B FUSE FUEL BALANCE PUMP FUEL GAUGE FUEL PUMP BALANCE MODULE (INSIDE LEFT SIDE FRAME RAIL) FUEL PUMP BALANCE RELAY (ON FUEL PUMP BALANCE MODULE) FUEL PUMP PRIME CONNECTOR (LEFT SIDE OF ENG COMPT) FUEL PUMP RELAY (IN UNDER FUSE- RELAY CENTER) FUEL PUMP/OIL PRESSURE SWITCH GAUGES FUSE 4 GRN WIRE GRY WIRE HOT AT ALL TIMES UNDERHOOD FUSE/RELAY CENTER HOT IN RUN OR START I/P FUSE BLOCK IGN E FUSE INSTRUMENT CLUSTER INSTRUMENT CLUSTER SYSTEM LT BLU WIRE LT GRN WIRE NCA WIRE ORG/ WIRE PNK PNK 8 9 WIRE PNK PNK PNK WIRE PNK WIRE PPL PRIMARY TANK FUEL LEVEL SENSOR RED WIRE SERVICE ENGINE SOON INDICATOR SERVICE THROTTLE SOON INDICATOR TAN WIRE VEHICLE SPEED INPUT W/ DUAL TANKS W/O DUAL TANK W/O DUAL TANK W/ DUAL TANKS WAIT TO WATER IN FUEL INDICATOR WATER IN-FUEL SENSOR (ON FUEL FILTER/ MANAGER) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

"SERV ENG SOON" IND ENGINE SHUTOFF SOL OUT "SERV THROTTLE SOON" IND 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 ENG-I FUSE FUEL SOL MODULE (5 VREF) FUSIBLE LINK FUSIBLE LINK FUSIBLE LINK GLOW GLOW PLUG 3 PLUG 1 GLOW PLUG 2 GLOW PLUG 4 GLOW PLUG 5 GLOW PLUG 6 GLOW PLUG 7 GLOW PLUG 8 GLOW PLUG OUTPUT GLOW PLUG RELAY (TOP LEFT REAR OF ENGINE) GRD GRY WIRE HOT AT ALL TIMES FUSIBLE LINK HOT IN RUN OR START LT GRN WIRE NCA 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 TAN WIRE TAN/WHT WIRE UNDERHOOD FUSE/RELAY CENTER WASTEGATE SOL ENGINE SHUTOFF SOL OUT WASTEGATE SOLENOID (TOP LEFT REAR OF ENGINE) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1226 1225 RANGE MODE SEL C RANGE MODE SEL B RANGE MODE SEL A 27 28 29 30 31 PPL 3/2 SHIFT SOL. PRESSURE CONTROL SOLENOID VALVE 7 8 9 10 12 13 14 15 VSS RTN GROUND A/C REQUEST SIG A/C SYSTEM A/T FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH ANTI-LOCK BRAKES SYSTEM AUTOMATIC TRANSMISSION BLK WIRE BLK/WHT WIRE BLU WIRE BLU/WHT WIRE BOOST PRESSURE SENSOR BRN WIRE BRN/WHT (M/T) WIRE BRN/WHT WIRE CRUISE CONTROL SWITCH DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE DK PNK WIRE ECT TEMP SENS IN BARO SENSOR INPUT GRN WIRE GRY WIRE GRY/BLK WIRE INTAKE MAN AIR TEMP SENS APP 2 SIG GLOW PLUG RELAY FORCE MTR LOW LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT PNK WIRE MAP SENS INPUT FORCE MTR HI 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 WIRE PNK/BLK WIRE POWERTRAIN CONTROL MODULE (PCM) (BEHIND RIGHT SIDE OF DASH, NEAR BLOWER MOTOR) PPL PPL (A/T) BRAKE SW IN BRAKE SWITCH INPUT CRUISE CTRL SW ENGAGE PPL (OR BRN/WHT) WIRE PPL/WHT WIRE RADIO RED WIRE RED/BLK WIRE RESUME SENSOR GND SET- SHIFT SOL. SHIFT SOL. TAN WIRE TAN/BLK WIRE TIMING STEPPER MTR (HIGH) 3 MODE CRUISE PPL SENSOR GND SENSOR GND APP 1 SIG TIMING STEPPER MTR (LOW) TIMING STEPPER MTR (LOW) TRANSMISSION SPEED INPUT TRANSMISSION TEMP INPUT TRANSMISSION TEMPERATURE SENSOR TRANSMISSIONS SYSTEM VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS SIG VSS SIG VSS HI VSS OUTPUT VSS OUTPUT WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK 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