GMC Pickup C2500 (1985-2000) org/ Wiring diagrams

BLK WIRE BRAIDED GROUND STRAP CARGO DOOR JAMB SWITCH (SUBURBAN/ UTILITY ONLY) COURTESY LAMPS CTRL CTSY FUSE 3 DOME DEFEAT DOOR JAMB DOOR LOCK CONTROL MODULE (IN FRONT OF LEFT REAR WHEELWELL) FRONT DOME/ READING LAMPS GRY WIRE HEADLAMP, PANEL DIMMER SWITCH DOME LAMP DEFEAT HORN FUSE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK GAGES FUSE 4 I/P COMPART- MENT BOX LAMP I/P FUSE BLOCK IGN SW INTERIOR LAMP CONTROL MODULE (UNDER CENTER OF DASH) LAMP OUT LEFT FRONT DOOR COURTESY LAMP (IF EQUIPPED) LEFT FRONT DOOR JAMB SWITCH LEFT I/P COURTESY LAMP LEFT ILLUMINATED VANITY MIRROR LEFT REAR DOOR COURTESY LAMP (IF EQUIPPED) LEFT REAR DOOR JAMB SWITCH (IF EQUIPPED) MIRRORS SYSTEM NCA WIRE ORG/ WIRE OVERHEAD CONSOLE LAMPS CIRCUIT PNK PNK WIRE PNK WIRE PPL REAR DOME/ READING LAMPS (IF EQUIPPED) REMOTE CONTROL DOOR LOCK RECEIVER (BEHIND CENTER OF DASH) RIGHT FRONT DOOR COURTESY LAMP (IF EQUIPPED) RIGHT FRONT DOOR JAMB SWITCH RIGHT I/P COURTESY LAMP RIGHT ILLUMINATED VANITY MIRROR RIGHT REAR DOOR COURTESY LAMP (IF EQUIPPED) RIGHT REAR DOOR JAMB SWITCH (IF EQUIPPED) UNDERHOOD FUSE/RELAY CENTER UNDERHOOD LAMP W/ OVERHEAD CONSOLE W/ RKE W/O OVERHEAD CONSOLE W/O RKE W/O RKE W/ RKE WHT WIRE

B+ SHOCK GRD TAMPER BLK WIRE BODY CONTROL MODULE (IN CENTER CONSOLE) CARGO DOOR JAMB SWITCH CTSY FUSE 3 DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DL BLU/WHT WIRE DOOR LOCK DOOR UNLOCK DOOR LOCK INVERSION MODULE (BEHIND LEFT SIDE OF DASH) DOOR UNLOCK DOOR LOCK GRD B+ HEADLIGHT SYSTEM HORNS SYSTEM HOT AT ALL TIMES I/P FUSE BLOCK LEFT FRONT DOOR JAMB SWITCH LEFT REAR DOOR JAMB SWITCH LIFTGATE JAMB SWITCH LT BLU WIRE LT GRN WIRE ORG/ WIRE PPL RIGHT FRONT DOOR JAMB SWITCH RIGHT REAR DOOR JAMB SWITCH SECURITY LED (IN CENTER OF FLOOR CONSOLE) SHOCK SENSOR (IN CENTER CONSOLE) TAN WIRE WHT/BLK WIRE

ASH TRAY LAMP BLK WIRE BODY CONTROL MODULE (IN CENTER CONSOLE) BRN WIRE GARAGE DOOR OPENER LAMP HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES I/P FUSE BLOCK LEFT FRONT POWER WINDOW SWITCH LEFT REAR HEATED SEAT SWITCH LEFT REAR POWER WINDOW SWITCH OFF ORG/ WIRE PARADE MODE SW PARK PARK LPS FUSE 9 POWER OUTSIDE REARVIEW MIRROR SWITCH REAR STEREO CONTROLLER REAR WINDOW LOCKOUT SWITCH RHEO- STAT RIGHT FRONT POWER WINDOW SWITCH RIGHT REAR HEATED SEAT SWITCH RIGHT REAR POWER WINDOW SWITCH

AUDIO ALARM MODULE (ON CONVENIENCE CENTER) AUTOMATIC TRANSFER CASE CONTROL SWITCH (LUXURY) AUTOMATIC TRANSFER CASH SELECT SWITCH AUXILIARY HEATER CONTROL BASE BLK WIRE CARGO LAMP SWITCH (PICKUP ONLY) TRANSFER CASE SWITCH CONVEN- IENCE CENTER DAYTIME RUNNING LAMP (DRL)/ RADIO OVERRIDE SWITCH DAYTIME RUNNING LAMPS (DRL)/ RADIO OVERRIDE SWITCH DISPLAY DIM SIG DISPLAY DISPLAY DIM DIM SIG SIG FOG LAMP SWITCH FRONT AUXILIARY HVAC CONTROL LAMP GRN WIRE GRY WIRE HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES HVAC CONTROL LAMP I/P FUSE BLOCK ILLUM FUSE 14 ILLUMINATION INFLATABLE RESTAINT I/P MODULE SWITCH INSTRUMENT CLUSTER LIFTGATE RELEASE SWITCH (SUBUR- BAN/ UTILITIY ONLY) LUXURY OFF ORG/ WIRE PARADE MODE SW PARK PARK LPS FUSE 9 PICKUP/ EXTENDED CAB ONLY PPL PPL PPL RADIO RADIO INFLATABLE RESTAINT I/P MODULE SWITCH REAR AUXILIARY HVAC CONTROL LAMP REAR AUXILIARY HVAC CONTROL SWITCH REAR WINDOW WIPER/ WASHER SWITCH RHEO- STAT SUBURBAN, UTILITY ONLY SWITCH (SUBUR- BAN/ UTILITIY ONLY) TRANSFER CASE SHIFT ILLUMINATION LAMP TRANSFER CASE SWITCH WHT WIRE

BLK WIRE COURTESY LAMPS CIRCUIT CTSY FUSE 3 FRONT DOME/ READING LAMPS HEADLAMP, PANEL DIMMER SWITCH COURTESY LAMPS HOT AT ALL TIMES I/P FUSE BLOCK INT LAMP OUTPUT ORG/ WIRE OVERHEAD CONSOLE READING LAMPS REAR DOME READING LAMPS REMOTE CONTROL DOOR LOCK RECEIVER (W/RKE) (BEHIND CENTER OF DASH) WHT WIRE

BLK/WHT WIRE BRN WIRE CAPACITOR DK GRN/WHT WIRE ELECTRONIC POWER STEERING SYSTEM SECURITY INDICATOR ENGINE CONTROLS SYSTEM EVO SOL FD EVO SOL OUT EVO/PASSLOCK MODULE (UNDER CENTER OF DASH) FILTER (MOLDED IN STEERING COLUMN HARNESS) 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 SENSOR REF SIGNAL GRD 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 STEERING HANDWHEEL SPEED SENSOR (SENSOR GROUND) WHT WIRE YEL WIRE

1-2 SHIFT SOL LT 16 17 18 PPL 2-3 SHIFT SOLENOID 3-2 SHIFT SOLENOID AIR INJECTION REACTION PUMP MOTOR (LEFT FRONT OF ENG COMPT) AIR INJECTION REACTION PUMP RELAY (CALIFORNIA) (UNDERHOOD FUSE/ RELAY CENTER) AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH AUX-B FUSE 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 EVAPORATIVE EMISSIONS (EVAP) CANISTER VENT VALVE (LEFT SIDE OF ENGINE COMPT) EXHAUST GAS RECIRCULATION (EGR) VALVE (FRONT OF ENGINE NEAR THERMOSTAT HOUSING) FUEL INJ 1 FUEL INJ 2 FUEL INJ 3 FUEL INJ 4 FUEL INJ 5 FUEL INJ 6 FUEL INJ 7 FUSE GRN WIRE GRY WIRE HOT AT ALL TIMES HOT IN RUN, START HOT IN RUN, START UNDER HOOD FUSE/RELAY CENTER LT BLU WIRE LT BLU/BLK WIRE LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE LT PNK WIRE NCA WIRE ORG/ WIRE PNK FUEL INJ 8 WIRE PNK PNK 1 2 3 4 5 6 7 8 WIRE PNK PNK PNK 3 4 5 6 7 8 9 10 11 12 13 14 WIRE PNK PNK PNK PNK PNK WIRE PNK PNK PNK PNK WIRE PNK PNK WIRE PNK WIRE PNK/BLK WIRE PPL PPL LT PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RED WIRE RED/BLK WIRE SOLENOID CHECK VALVE TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TCC SOLENOID TORQUE CONVERTER CLUTCH PULSE WIDTH MODULATION SOLENOID TRANS FLUID TEMPERATURE SENSOR WHT WIRE YEL WIRE YEL/BLK WIRE

16 17 18 PPL 39 40 41 PPL ACTUAL GAS AF ECU BAT AF ECU GND AF ECU IGN ALTERNATIVE FUEL ENGINE CONTROL UNIT (LEFT SIDE OF ENGINE COMPT) BLK WIRE BRN WIRE BRN/WHT WIRE CLASS 2 DATA CNG FUSE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECT INPUT EGR SENS F PMP RLY FPS SIG FPS/FTS GND FTS SIG FUEL LEV OUT FUEL PRESSURE SENSOR (END OF CNG FUEL TANK) FUEL TEMPERATURE SENSOR (END OF CNG FUEL TANK) GAS FLOW OUT GAUGE SEL SW GRY WIRE HI PRES LO HOT AT ALL TIMES UNDER HOOD FUSE/RELAY CENTER HOT IN RUN, BULB TEST AND START IAT INPUT IGN E FUSE IND CTRL LOW PRES LO LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE MAF INPUT MAP INPUT MIL CTRL MIL OUT NGO ENABLE ORG/ WIRE PNK 2 3 4 5 6 7 WIRE PNK 24 25 26 27 28 29 30 31 32 33 34 35 36 37 WIRE PNK PNK PNK 3 4 5 6 7 8 9 10 11 12 13 14 WIRE PNK PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RED/BLK WIRE RELAY CTRL SENSOR GND SERIAL DATA TAN WIRE TAN/WHT WIRE TP SENSOR VSS INPUT WHT WIRE YEL WIRE YEL/BLK WIRE

32 33 PPL 39 40 41 PPL AF FUEL PUMP RELAY (LEFT OF ENGINE COMPT) BLK WIRE BRN WIRE BRN/WHT WIRE DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE FUEL GAUGE RELAY (LEFT OF ENGINE COMPT) FUEL GAUGE SELECT SWITCH GAS MASS SENSOR (RIGHT FRONT OF ENGINE) GRY WIRE GRY/BLK WIRE HIGH PRESSURE LOCK-OFF SOLENOID (END OF CNG FUEL TANK) IGNITION RELAY (LEFT OF ENGINE COMPT) LOCK-OFF RELAY (LEFT OF ENGINE COMPT) LOW PRESSURE LOCK-OFF SOLENOID (RIGHT MIDDLE OF ENGINE) LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE MIXTURE CONTROL VALVE MOTOR (RIGHT FRONT OF ENGINE) NCA WIRE ORG/ WIRE PNK 2 3 4 5 6 7 WIRE PNK 24 25 26 27 28 29 30 31 32 33 34 35 36 37 WIRE PNK PNK PNK 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 WIRE PNK PNK PNK WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE RED/BLK WIRE TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE YEL/BLK WIRE

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 BRAKE CONTROL MODULE (EBCM) (ON LEFT SIDE OF ENGINE COMPT) 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 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 INPUT BRAKE SW INPUT 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 INPUT SERIAL DATA SIG MANUAL OR SELECTABLE ORG/ WIRE PNK 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 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 SENSOR INPUT STOPLAMP/ CLUTCH SWITCH INPUT VCM SIG 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) TRANSMISSIONS SYSTEM UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE