GMC Pickup C2500 (1985-2000) hot at all times Wiring diagrams

BATTERY JUNCTION BLOCK (RIGHT REAR ENGINE COMPARTMENT, AT COWL) BLK WIRE CARGO LAMP CARGO LAMP SWITCH CONVENIENCE CENTER COURTESY SWITCH CTSY FUSE FRONT DOME LAMP FUSE BLOCK HOT AT ALL TIMES IN-LINE FUSE LEFT FRONT DOOR JAMB SWITCH ORG/ WIRE ORG/BLK WIRE PANEL DIMMER SWITCH RED WIRE RIGHT FRONT DOOR JAMB SWITCH UNDERHOOD REEL LAMP WHT WIRE

AUX FUSE 22 AUXILIARY LEAD (TAPED TO HARNESS) BACK-UP LIGHTS CIRCUIT BLK WIRE BLU WIRE BRN WIRE CARGO LAMP CARGO LAMP SWITCH CENTER HIGH MOUNT STOP LAMP CHMSL LAMP (2 BULBS) CRUISE CONTROL SYSTEM CTSY FUSE 3 DK BLU WIRE DK GRN WIRE GRN WIRE GRY WIRE HAZARD NORMAL HEADLAMP, PANEL DIMMER SWITCH HEADLIGHTS SYSTEM HOT AT ALL TIMES HOT AT ALL TIMES UNDER- HOOD FUSE- RELAY CENTER (LEFT REAR OF ENGINE COMPT.) HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRU- MENT CLUSTER RIGHT TURN INDIC LEFT LEFT FRONT MARKER LAMP LEFT FRONT PARK/ TURN LAMPS LEFT SPOTLAMP ASSEMBLY (POLICE PACKAGE) LEFT TAIL/ STOP/ TURN LAMP DK DK LEFT TURN INDIC LICENSE LICENSE LAMP LAMPS LT BLU WIRE LT GRN WIRE MAXI FUSE 2 NCA WIRE OFF ORG/ WIRE PARK PARK LPS FUSE 9 PICKUP PNK WIRE POLICE PACKAGE (1999 ONLY) PPL REAR CLEARANCE LAMPS CIRCUIT RED WIRE RHEO- STAT RIGHT RIGHT FRONT MARKER LAMP RIGHT FRONT PARK/ TURN LAMPS RIGHT SPOTLAMP ASSEMBLY (POLICE PACKAGE) RIGHT TAIL/ STOP/ TURN LAMP ROOF MARKER LAMPS STOP- LAMP RELAY (EXCEPT SUBUR- BAN/ UTILITY) STOP/ HAZ FUSE 1 STOPLAMP SWITCH (TOP OF BRAKE PEDAL) SUBURBAN/ UTILITY TRAILER TOW CONNECTOR TURN B/U FUSE 16 TURN PWR HAZ PWR FLSHR OUT GND TURN/ HAZARD SWITCH TURN/HAZARD FLASHER (ON CONVENIENCE CENTER) UNDER- HOOD FUSE RELAY CENTER (LEFT REAR OF ENGINE COMPT.) W/ DUAL REAR WHEELS W/ STEP BUMPER W/O STEP BUMPER WHT WIRE YEL WIRE

BLK WIRE BRN WIRE BULB CHECK DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P) DAYTIME RUNNING LAMPS RELAY (ENGINE COMPARTMENT FRONT PLENUM PANEL) DK BLU/WHT WIRE DRL FUSE FUSE BLOCK GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START GAUGES FUSE HTR A/C FUSE IGNITION LAMP FEED HI BEAM FEED HI BEAM INDICATOR OUTPUT TO RELAY GROUND INSTRUMENT CLUSTER LEFT HIGH BEAM HEADLAMP LEFT LOW BEAM HEADLAMP LT GRN WIRE LT GRN/BLK WIRE LT LT OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PICKUP ONLY PNK/BLK WIRE RIGHT HIGH BEAM HEADLAMP RIGHT LOW BEAM HEADLAMP SUBURBAN, UTILITY ONLY TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE BRN WIRE BULB CHECK DAYTIME RUNNING LAMP INDICATOR DAYTIME RUNNING LAMPS MODULE (BEHIND LEFT SIDE OF I/P) DAYTIME RUNNING LAMPS RELAY (ENGINE COMPARTMENT FRONT PLENUM PANEL) DK BLU/WHT WIRE DRL FUSE FUSE BLOCK GRN WIRE HEAD PARK HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT IN RUN HOT IN RUN, BULB TEST OR START GAUGES FUSE HTR A/C FUSE IGNITION LAMP FEED HI BEAM FEED HI BEAM INDICATOR OUTPUT TO RELAY GROUND INSTRUMENT CLUSTER LEFT HEADLAMP ASSEMBLY LT GRN WIRE LT GRN/BLK WIRE LT LT OFF OFF HEAD ORG/ WIRE PARK PARK BRAKE WARNING SWITCH (AT PARK BRAKE, UNDER LEFT SIDE OF I/P) PICKUP ONLY PNK/BLK WIRE RIGHT HEADLAMP ASSEMBLY SUBURBAN, UTILITY ONLY TAN WIRE TAN/WHT WIRE WHT WIRE YEL WIRE

BLK WIRE GRN WIRE HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HOT AT ALL TIMES LEFT HEADLAMP ASSEMBLY LO HI LT GRN WIRE LT INSTRUMENT CLUSTER OFF OFF HEAD HEAD PARK PARK RIGHT HEADLAMP ASSEMBLY TAN WIRE YEL WIRE

BLK WIRE BRN WIRE CONVENIENCE CENTER DK BLU WIRE FOG LAMP ON INDICATOR FOG LAMP RELAY (BEHIND LEFT SIDE OF I/P) FOG LAMP SWITCH SOLID STATE SWITCH FUSE BLOCK GRN WIRE GRY WIRE HEADLAMP DIMMER SWITCH HEADLIGHT SWITCH ASSEMBLY HI BEAM INDICATOR HI LO HOT AT ALL TIMES HOT AT ALL TIMES ACC-BATT CIRCUIT BREAKER ILLUM LAMP LEFT LOW BEAM HEAD- LAMP LT GRN WIRE LT INSTRUMENT CLUSTER LT LT OFF OFF HEAD HEAD PARK ORG/BLK WIRE PARK PNL LPS FUSE PPL PPL PPL RIGHT FOG LAMP LEFT FOG LAMP RIGHT HIGH BEAM HEAD- LAMP LEFT HIGH BEAM HEAD- LAMP RIGHT LOW BEAM HEAD- LAMP TAN WIRE VARIABLE VOLTAGE W/ HEADLIGHT SWITCH IN PARK OR HEAD, RHEOSTAT ADJUSTED WHT WIRE YEL WIRE

BASE BLK WIRE BODY CONTROL MODULE (IN CENTER CONSOLE) CONVENIENCE CENTER (UNDER LEFT SIDE OF DASH) DK GRN WIRE HORN FUSE HORN SWITCH HOT AT ALL TIMES LEFT HORN (FRONT OF VEHICLE) RIGHT HORN LUXURY LUXURY BASE ORG/ WIRE REMOTE CONTROL DOOR LOCK RECEIVER (BEHIND CENTER OF DASH) STEERING WHEEL HORN SLIP RING UNDERHOOD FUSE BLOCK (LEFT REAR OF ENGINE COMPT) UNDERHOOD FUSE BLOCK HORN RELAY VEHICLE INTERFACE UNIT RECEIVER (UNDER- NEATH RIGHT REAR SEAT)

BLK WIRE BRN WIRE ENDGATE MARKER LAMPS FRONT MARKER, PARK/TURN LAMPS FUSE BLOCK- I/P HEAD OFF HEADLIGHT SWITCH ASSEMBLY HOT AT ALL TIMES LEFT FRONT CLEARANCE LAMP LEFT REAR CLEARANCE LAMP LEFT REAR FENDER ORG/ WIRE PARK PARK LPS FUSE RIGHT FRONT CLEARANCE LAMP RIGHT REAR CLEARANCE LAMP RIGHT REAR FENDER TAIL/STOP/TURN, LICENSE LAMPS) TRAILER TOW

4.3L ONLY 423 3 121 PNK WIRE ACCY BLK WIRE BRN WIRE BRN/WHT WIRE BULB TEST DISTRIBUTOR (CENTER REAR OF ENGINE) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE SENSOR (FRONT OF ENGINE) GAUGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK (BEHIND LEFT SIDE OF I/P) IGNITION COIL (CENTER REAR OF ENGINE) IGNITION SWITCH INSTRUMENT CLUSTER KNOCK SENSOR (4.3L ONLY) (REAR OF ENGINE) KNOCK SENSOR (RIGHT SIDE OF ENGINE, BELOW EXHAUST MANIFOLD) LINEAR EGR VALVE (7.4L ONLY) (RIGHT SIDE TOP OF ENGINE) LOCK OFF LT GRN WIRE MANIFOLD ABSOLUTE PRESSURE SENSOR (RIGHT REAR TOP OF ENGINE) NCA WIRE ORG/ WIRE PNK WIRE PPL PPL 1 2 3 4 PPL/WHT WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON INDICATOR TACHOMETER TEST LEAD TAN WIRE TAN/BLK WIRE THROTTLE POSITION SENSOR (RIGHT SIDE OF THROTTLE BODY) UPSHIFT LAMP WHT WIRE WHT/BLK WIRE YEL WIRE

4.3L ONLY BLK WIRE BLK/WHT WIRE BRN WIRE DATA LINK CONNECTOR (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ECM-B MINI FUSE FUEL PUMP AND SENDER FUEL PUMP OIL PRESSURE SWITCH (TOP REAR OF ENGINE NEAR DISTRIBUTOR) FUEL PUMP PRIME CONN- ECTOR FUEL PUMP RELAY (UNDERHOOD FUSE/RELAY CENTER) GRY WIRE HEATED OXYGEN SENSOR (IN EXHAUST Y-PIPE) HOT AT ALL TIMES IDLE SPEED CONTROL ACTUATOR SOLENOID (7.4L ONLY) (SIDE OF THROTTLE BODY UNIT) INSTRUMENT CLUSTER LT GRN/BLK WIRE OIL PRESS IN ORG/ WIRE PNK WIRE PPL PPL/WHT WIRE RED WIRE TACH IN TAN WIRE UNDERHOOD FUSE/RELAY CENTER (LEFT REAR OF ENGINE COMPT) VEHICLE SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF I/P) VSS IN WHT WIRE WHT/BLK WIRE