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

A/C COMP FUSE AUX FAN CTRL AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (IN UNDERHOOD FUSE/RELAY CENTER) BLK WIRE DK BLU WIRE DK GRN WIRE FAN REQ HEATER AND A/C CONTROL MODULE HOT AT ALL TIMES HOT IN RUN OR START ORG/ WIRE RECIRCULATION DOOR MOTOR (ON A/C- HEATER HOUSING) RED WIRE RELAY CTRL UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (LEFT REAR OF ENGINE COMPT)

A/C COMP FUSE AUX FAN CTRL AUX FAN FUSE AUXILIARY COOLING FAN MOTOR AUXILIARY COOLING FAN RELAY (IN UNDERHOOD FUSE/RELAY CENTER) BLK WIRE DK BLU WIRE DK GRN WIRE FAN REQ HEATER AND A/C CONTROL MODULE HOT AT ALL TIMES HOT IN RUN OR START ORG/ WIRE RECIRCULATION DOOR MOTOR (ON A/C- HEATER HOUSING) RED WIRE RELAY CTRL UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE (LEFT REAR OF ENGINE COMPT)

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

3 22 SPEED SENSOR OUTPUT BLK WIRE BLK/WHT WIRE BLU WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE CLUTCH PEDAL POSITION SWITCH (TOP OF CLUTCH PEDAL) CRUISE CONTROL MODULE (LEFT REAR OF ENGINE COMPARTMENT) CRUISE CONTROL SWITCH CRUISE ENGAGE INPUT CRUISE FUSE 6 CRUISE ON INPUT SET/COAST SIG RESUME/ACCEL SIG DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE CONTROL SYSTEM EXTERIOR LIGHT SYSTEM GRY WIRE GRY/BLK WIRE HOT AT ALL TIMES HOT IN RUN I/P FUSE BLOCK (LEFT SIDE OF DASH, LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE M/T A/T M/T A/T (I/P HARN, LEFT REAR OF ENGINE COMPT) OFF (OR ON (OR PNK) WIRE ORG/ WIRE PPL PPL SHIFT INTER- LOCK SYSTEM PPL/WHT WIRE STOP/HAZ FUSE 1 STOPLAMP SWITCH (TOP OF BRAKE PEDAL) VCM SIGNAL SPEED SENSOR INPUT VEHICLE CONTROL MODULE (VCM) (LEFT SIDE OF ENGINE COMPT) VEHICLE SPEED SENSOR (VSS) (LEFT SIDE OF TRANSMISSION) VSS HIGH VSS LOW WHT WIRE

BLK WIRE CARGO LAMP CTRL CTSY FUSE 3 DOME DEFEAT DOME DEFEAT IGN SW DOOR JAMB FRONT DOME AND READING LAMP GRY WIRE HEADLAMP AND PANEL DIMMER SWITCH DOME LAMP DEFEAT COURTESY LAMPS HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P COMPARTMENT BOX LAMP I/P FUSE BLOCK I/P FUSE BLOCK GAGES FUSE 4 IGN SW INTERIOR LAMP CONTROL MODULE (UNDER CENTER OF DASH) LAMP OUT LEFT I/P COURTESY LAMP LEFT ILLUMINATED VANITY MIRROR MIRRORS SYSTEM NCA WIRE ORG/ WIRE PNK WIRE PPL (NOT USED) PPL PPL REMOTE CONTROL DOOR LOCK RECEIVER (BEHIND CENTER OF DASH) RIGHT FRONT DOOR JAMB SWITCH LEFT FRONT DOOR JAMB SWITCH RIGHT I/P COURTESY LAMP RIGHT ILLUMINATED VANITY MIRROR UNDERHOOD FUSE-RELAY CENTER HORN FUSE UNDERHOOD LAMP UNDERHOOD REEL LAMP W/ RKE W/O RKE WHT WIRE

39 1807 PNK PPL WIRE BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (DLC) (UNDER LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) PPL DIESEL DK GRN WIRE DK GRN/WHT WIRE ELECTRONIC VARIABLE ORIFICE (EVO)/ PASSLOCK MODULE (UNDER CENTER OF DASH) EVO SOLENOID OUT EVO FEED SWS POSIT SIG VSS SIGNAL INPUT GAS GAUGES FUSE 4 GROUND IGNITION DATA SENSOR RETURN 5 VOLT REF BATTERY GRY WIRE HOT AT ALL TIMES HOT IN RUN OR START I/P FUSE BLOCK (UNDER LEFT SIDE OF DASH) LT BLU WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE SECURITY/STRG FUSE 21 SENSOR RETURN STEERING ASSIST CONTROL SOLENOID (PART OF POWER STEERING PUMP) STEERING HANDWHEEL SPEED SENSOR (ON STEERING COLUMN, NEAR FIREWALL) STEERING VOLT WHEEL POSIT REF SIGNAL VEHICLE CONTROL MODULE (ON LEFT SIDE OF ENGINE COMPARTMENT) VEHICLE SPEED SENSOR BUFFER (BEHIND RIGHT SIDE OF DASH) VSS SIG OUT 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

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND AIR TEMP DR SENSOR MODE SIGNAL BATTERY IGNITION GROUND DEFOGGER ELEMENT BLK WIRE BLOWER FUSE 3 BLOWER MOTOR (UNDER RIGHT SIDE OF DASH) BLOWER RESISTOR (ON BLOWER MOTOR HOUSING) BLOWER SWITCH BRN WIRE DK BLU WIRE DK GRN WIRE FRONT MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FRONT TEMPERATURE DOOR MOTOR FUSE BLOCK GRY WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C- HEATER BLOWER HOUSING) HOT AT ALL TIMES HOT IN RUN HTR A/C FUSE 12 HVAC CONTROL MODULE LT BLU WIRE OFF LO ORG/ WIRE PPL REAR DEFOGGER SYSTEM RECIRC CTRL IGNITION RECIRCULATION DOOR MOTOR RED WIRE TAN WIRE UNDERHOOD FUSE-RELAY CENTER WHT WIRE YEL WIRE

1-2 SHIFT SOL LT 2-3 SHIFT SOLENOID AIR INJECTION REACTION PUMP CLUTCH (ON FRONT OF AIR PUMP) AIR INJECTION REACTION RELAY (UNDERHOOD FUSE/ RELAY CENTER) AUTOMATIC TRANSMISSION AUTOMATIC TRANSMISSION FLUID PRESSURE (TFP) MANUAL VALVE POSITION SWITCH BLK WIRE BLK/WHT WIRE BLU WIRE BRN WIRE DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE EXHAUST GAS RECIRCULATION (EGR) VALVE (ON TOP LEFT SIDE OF ENG) FLUID TEMPERATURE SENSOR 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 IN RUN, START 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 PNK 1 2 3 4 5 WIRE PNK PNK PNK PNK 3 4 5 6 WIRE PNK PNK PNK PNK PNK WIRE PNK PNK WIRE PNK PPL WIRE PNK WIRE PNK/BLK WIRE PPL PPL LT PPL/WHT WIRE PRESSURE CONTROL SOLENOID VALVE RED WIRE RED/BLK WIRE TAN WIRE TORQUE CONVERTOR CLUTCH PULSE WIDTH MODULATION SOLENOID UNDERHOOD FUSE/RELAY CENTER WHT WIRE YEL WIRE YEL/BLK WIRE

A/C REQUEST SIGNAL A/T AIR CONDITIONING SYSTEM AIR INLET VLV MTR CTLR 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 A/T 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 BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE EGR VLV FEED 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 COIL IGNITION CONTROL MODULE (ON REAR OF INTAKE MANIFOLD) IGNITION FEED IGN TIMING SIG. IGN COIL OUT IGNITION PRESSURE SWITCH INPUT PRESSURE SWITCH INPUT LT BLU/BLK WIRE LT BLU/WHT WIRE LT VSS SERIAL INPUT DATA SIG MANUAL OR AUTOMATIC 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 SPEED SENSOR SPEED STOPLAMP/ VCM SENSOR CLUTCH SIG INPUT SWITCH INPUT STOPLAMP SWITCH (TOP OF BRAKE PEDAL) SWITCH SIGNAL TRANSFER CASE CONTROL MODULE (UNDER DASH ON STEERING COLUMN SUPPORT BRACKET) 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