Chevrolet Pickup C2500 (1988-2000) underhood fuse-relay center Wiring diagrams

1 2 3 4 5 6 7 8 9 10 ILLUMINATION GROUND A/C DISABLE AUX FAN CTRL 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 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 FUSE 3 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 MODE DOOR MOTOR (ON FRONT A/C-HEATER HOUSING) FUSE BLOCK GRY WIRE GRY/BLK WIRE HIGH BLOWER RELAY (ON TOP OF FRONT A/C-HEATER HOUSING) HOT AT ALL TIMES HOT AT ALL TIMES UNDERHOOD FUSE-RELAY CENTER 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-RELAY CENTER VALVE CTRL AIR TEMP DR SENSOR MODE SIGNAL A/C SWITCH VEHICLE CONTROL MODULE (LEFT SIDE OF ENGINE COMPT) WATER VALVE (SUBURBAN, UTILITY, CREW CAB ONLY) (RIGHT CENTER OF INTAKE AREA) WHT WIRE YEL WIRE

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 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

A/C COMP MINI FUSE A/C MAXI FUSE 3 MAXI FUSE 4 A/C RELAY AUX FAN RELAY MINI FUSE AUXILIARY COOLING FAN RELAY BLK WIRE BLK/RED WIRE BLOWER LOW RELAY BLOWER RELAY BLU WIRE BRAKE LAMP RELAY UNDERHOOD FUSE-RELAY CENTER CARGO LAMP SWITCH (PICK-UP ONLY) CONVENIENCE CENTER CONVENIENCE CONVENIENCE CENTER CENTER CTSY FUSE 3 DAYTIME LEFT RUNNING COURTESY LAMPS LAMP RELAY DIESEL DIESEL EXCEPT DIESEL DIESEL GASOLINE DIODE DRL/FOG FUSE 15 ECM-B MINI FUSE ELECTRONIC CONVENIENCE CENTER BRAKE CONTROL MODULE FRONT DOME/ READING LAMPS FUEL PUMP OIL PRESSURE SWITCH AND SENDER FUEL PUMP RELAY UNDERHOOD FUSE-RELAY CENTER FUSIBLE LINK (10 GA-RUST) GAS GENERATOR HEADLAMP AND PANEL DIMMER SWITCH HEATER AND A/C CONTROL SWITCH HORN MINI FUSE HORN RELAY I/P COMPARTMENT LAMP I/P FUSE BLOCK INTERIOR LAMP CONTROL MODULE LEFT BATTERY (DIESEL) LEFT ILLUMINATED VANITY MIRROR MAXI FUSE MAXI FUSE 2 MAXI FUSE 8 ORG/ WIRE PK LPS FUSE 9 POWERTRAIN CONTROL MODULE (DIESEL) REAR DOME READING LAMPS RED WIRE REMOTE BATTERY STUD RIGHT BATTERY RIGHT COURTESY LAMP RIGHT FRONT DOOR COURTESY LAMP RIGHT REAR DOOR COURTESY LAMP RR-DEFOG MINI FUSE STARTER MOTOR SOLENOID TO FUSIBLE LINK (DIAGRAM 4 OF 4) TO UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 2 OF 4) UNDERHOOD FUSE-RELAY CENTER UNDERHOOD LAMP UNDERHOOD REEL LAMP VEHICLE CONTROL MODULE (GASOLINE) YEL WIRE

AUDIO ALARM MODULE AUX/PWR FUSE 7 AUXILIARY POWER CONNECTOR BLK WIRE BRN WIRE CIG LTR FUSE 13 CIGAR LIGHTER CONVENIENCE CENTER CRANK FUSE 8 DATA LINK CONNECTOR DOOR REMOTE CONTROL LOCK DOOR LOCK RELAY RECEIVER FROM UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 1 OF 4) I/P FUSE BLOCK IGNITION SWITCH INSTRUMENT CLUSTER LEFT FRONT DOOR LOCK SWITCH LEFT FRONT RIGHT FRONT POWER DOOR LOCK DOOR LOCK AMPLIFIER SWITCH SWITCH RELAY LEFT POWER SEAT LOCK LOCK OFF OFF LOCK OFF M/T A/T MAXI FUSE 5 MAXI FUSE 6 MAXI FUSE 7 NCA WIRE ORG/ WIRE PNK WIRE POWER WDO CIRCUIT BREAKER PPL PWR-ACCY CIRCUIT BREAKER RADIO RADIO BATT FUSE 19 RADIO FUSE 17 REAR DOOR DOOR LOCK LOCK SWITCH CONTROL MODULE REAR WINDOW LOCKOUT SWITCH (4-DR) RED WIRE REMOTE CONTROL DOOR LOCK RECEIVER RIGHT FRONT DOOR LOCK SWITCH RIGHT FRONT POWER LUMBAR SEAT SWITCH RIGHT FRONT POWER POWER WINDOW WINDOW MASTER SWITCH SWITCH (2 DR, UTILITY) RR WIPER FUSE 23 WIPER FUSE 11 RUN WIRE STARTER RELAY UNDERHOOD FUSE-RELAY CENTER STOP/HAZ FUSE 1 SUBURBAN ONLY SUBURBAN/ UTILITY PICKUP T CASE FUSE 2 TCC/STOPLAMP SWITCH TO I/P FUSE BLOCK (DIAGRAM 4 OF 4) TO SECURITY/ STRG FUSE 21 (DIAGRAM 4 OF 4) TO UNDERHOOD FUSE-RELAY CENTER (DIAGRAM 3 OF 4) TRANS FUSE 20 TRANS- MISSION TRANSFER CASE CONTROL MODULE TURN/ HAZARD SWITCH UNDERHOOD FUSE-RELAY CENTER W/BENCH SEAT W/O BENCH SEAT WHT WIRE WINDSHIELD RADIO WIPER MOTOR MODULE YEL WIRE

4.3L PNK WIRE 7.4L 6.5L 7.4L W/ CALIFORNIA EMISSIONS OTHERS A/C CLUTCH RELAY A/T M/T AIR BAG FUSE 10 AIR INJECTION REACTION SECONDARY RELAY BACKUP LAMP SWITCH BLK WIRE CAMSHAFT EXHAUST POSITION GAS SENSOR RECIRCULATION VALVE CONVENIENCE CENTER DAYTIME AUDIO RUNNING ALARM MODULE LAMPS RELAY DIESEL ONLY PNK WIRE EGR SOLENOID ELECTROCHROMATIC MIRROR W/ COMPASS ELECTRONIC INJECTION PUMP ENG-1 MINI FUSE EVAPORATIVE EMISSION CANISTER VENT EVAPORATIVE FUEL EMISSIONS PUMP CANISTER PURGE BALANCE SOLENOID VALVE RELAY FROM IGNITION SWITCH (DIAGRAM 2 OF 4) FUEL EGR GLOW WATER-IN- HEATER VENT PLUG FUEL SOLENOID CONTROL SENSOR MODULE FUEL FUEL FUEL INJECTOR INJECTOR INJECTOR FUEL FUEL INJECTOR INJECTOR FUEL INJECTOR FUEL PUMP BALANCE MODULE FUEL SOL MINI FUSE ECM 1 MINI FUSE FUEL TANK DAYTIME SENDER RUNNING I/P MODULE LAMPS CLUSTER MODULE (4.3L) GASOLINE DIESEL 5.0L, 5.7L 4.3L GAUGES FUSE 4 HEATED HEATED MASS OXYGEN OXYGEN AIRFLOW SENSOR 1 SENSOR 2 SENSOR HEATED HEATED OXYGEN OXYGEN SENSOR 4 SENSOR 3 I/P FUSE BLOCK IGN E MINI FUSE IGNITION CRANK- CONTROL SHAFT MODULE POSITION SENSOR IGNITION CRANK- FUEL CONTROL SHAFT INJECTOR MODULE POSITION SENSOR INFLATABLE RESTRAINT I/P MODULE ENABLE SWITCH INFLATABLE RESTRAINT SENSING AND DIAGNOSTIC MODULE M/T MASS AIR FLOW SENSOR NCA WIRE PNK WIRE POWER STEERING CONTROL MODULE POWERTRAIN CONTROL MODULE TRANSFER CASE CONTROL MODULE TURN B/U FUSE 16 TURN SIGNAL SWITCH UNDERHOOD FUSE-RELAY CENTER VEHICLE CONTROL MODULE VEHICLE IGNITION CONTROL COIL MODULE WASTEGATE SOLENOID YEL 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 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

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