GMC Pickup C3500 (1985-2000) i/p fuse block Wiring diagrams

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR 450 450 551 413 451 417 (4.3L ONLY) BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) GAGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF DASH) PPL PPL PNK WIRE PPL/WHT WIRE RANGE MODE SELECTOR PRESSURE CONTROL SOLENOID RED WIRE RED/BLK WIRE RUN WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TCC SOL TCC/STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF TBI) TRANS FUSE 20 TRANSMISSION UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT WIRE WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

1-2 SHIFT SOL 2-3 SHIFT SOL 3-2 SHIFT SOL TRANS FLUID TEMP (TFT) SENSOR BLK WIRE BLK/WHT WIRE BLK/YEL WIRE BRAKE FUSE 18 BRN WIRE BRN/WHT WIRE DATA LINK CONNECTOR (BELOW LEFT SIDE OF DASH) DK BLU WIRE DK BLU/WHT WIRE ECM I FUSE ECM-B FUSE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (TOP FRONT OF ENGINE) GAGES FUSE 4 GRY WIRE HOT AT ALL TIMES HOT IN RUN HOT IN RUN OR START HOT IN RUN, BULB TEST OR START I/P FUSE BLOCK INSTRUMENT CLUSTER LT BLU/WHT WIRE LT GRN WIRE LT GRN/BLK WIRE ORG/ WIRE PNK WIRE POWERTRAIN CONTROL MODULE (PCM) (UNDER RIGHT END OF DASH) PPL PPL PNK WIRE PPL/WHT WIRE PRESSURE CONTROL SOLENOID RANGE MODE SELECTOR RED WIRE RED/BLK WIRE SERVICE ENGINE SOON SPEED SENSOR (LEFT REAR SIDE OF TRANSMISSION) TAN WIRE TCC/STOPLAMP SWITCH (ON BRAKE PEDAL BRACKET) THROTTLE POSITION SENSOR (RIGHT SIDE OF TBI) TRANS FUSE 20 TRANSMISSION TRANSMISSION INPUT SHAFT SPEED SENSOR (FRONT OF TRANSMISSION) UNDERHOOD FUSE/RELAY CENTER VEHICLE SPEED SENSOR BUFFER (UNDER RIGHT END OF DASH) WHT/BLK WIRE YEL WIRE YEL/BLK WIRE

BLK WIRE CARGO DOOR CONTACT SWITCH CIG LTR FUSE 13 CIRCUIT BREAKER A CONVENIENCE CENTER DOOR LOCK RELAY (UNDER CENTER OF I/P) GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK LEFT FRONT DOOR LOCK MOTOR SOLID STATE LEFT FRONT DOOR LOCK SWITCH LEFT REAR DOOR LOCK MOTOR SOLID (4 DOOR ONLY) STATE LOCK UNLOCK LT BLU WIRE ORG/ WIRE RIGHT FRONT DOOR LOCK MOTOR SOLID STATE RIGHT FRONT DOOR LOCK SWITCH RIGHT REAR DOOR LOCK MOTOR SOLID (4 DOOR ONLY) STATE SOLID STATE TAN WIRE UNLOCK LOCK UNLOCK RELAY LOCK RELAY UTILITY 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

AUTOMATIC DAY-NIGHT HEATING SENSOR ELEMENT (UPPER (UPPER LEVEL) LEVEL) BLK WIRE BLU WIRE BRN WIRE CTSY FUSE 3 DOWN ELECTRO- DEFOGGER CHROMIC SYSTEM MIRROR (HEATED CIRCUIT MIRROR) GRN WIRE GRY WIRE HOT AT ALL TIMES I/P FUSE BLOCK LEFT LEFT POWER OUTSIDE REARVIEW MIRROR LEFT/ RIGHT MOTOR LT GRN WIRE LT LT (OR (OR ORG/ WIRE PNK WIRE POWER OUTSIDE REARVIEW MIRROR SWITCH PPL PPL/WHT WIRE RED (OR YEL) WIRE RED WIRE RIGHT RIGHT POWER OUTSIDE REARVIEW MIRROR UP/ DOWN MOTOR WHT WIRE YEL WIRE

BLK WIRE BRN WIRE COLUMN HARNESS BREAKOUT) ENDGATE MARKER LAMPS EXTERIOR LAMPS CIRCUIT FROM TRAILER HARNESS BREAKOUT) HEADLAMP, PANEL DIMMER SWITCH HOT AT ALL TIMES I/P FUSE BLOCK LEFT REAR CLEAR- ANCE LAMP LEFT FRONT CLEAR- ANCE LAMP LEFT REAR FENDER LEFT TAIL/ STOP/ TURN LAMP OFF ORG/ WIRE PARK PARK LPS FUSE 9 RHEO- STAT RIGHT FRONT CLEAR- ANCE LAMP RIGHT REAR CLEAR- ANCE LAMP RIGHT REAR FENDER RIGHT TAIL/ STOP/ TURN LAMP

4 WHEEL CONTROL DRIVE MODULE LOW (UNDER RIGHT SIGNAL END OF I/P) 4 WHEEL DRIVE INPUT (NOT USED) AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE BRN/WHT WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE EHCU MODULE (NEAR MASTER CYLINDER) FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN PPL RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) SUBURBAN, YUKON TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE)

4 WHEEL CONTROL DRIVE MODULE LOW (UNDER RIGHT SIGNAL END OF I/P) 4 WHEEL DRIVE INPUT (NOT USED) AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE BRN/WHT WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE EHCU MODULE (NEAR MASTER CYLINDER) FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN PPL RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) SUBURBAN, YUKON TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE)

4 WHEEL DRIVE LOW (UNDER RIGHT END OF I/P) SIGNAL AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN CONTROL MODULE PPL PPL PPL RED WIRE RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE RELAY (RIGHT REAR OF ENG COMPT, NEAR BATTERY JUNCTION BLOCK) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE) TRANSFER CASE SYNCRONIZER

4 WHEEL DRIVE LOW (UNDER RIGHT END OF I/P) SIGNAL AUTOMATIC TRANSMISSION ONLY BLK WIRE BRN WIRE CONVENIENCE CENTER (UNDER LEFT SIDE OF I/P) DK BLU WIRE DK GRN WIRE FRONT AXLE ACTUATOR SOLENOID (RIGHT SIDE OF FRONT DRIVE AXLE) FRONT AXLE SOLENOID SWITCH (RIGHT REAR SIDE OF FRONT DRIVE AXLE) FUSE GRY WIRE HOT IN RUN I/P FUSE BLOCK INDICATOR LAMP INSTRUMENT CLUSTER LT BLU WIRE PANEL DIMMER SWITCH (ASSEMBLY) PANEL LPS FUSE PICKUP PNK/WHT WIRE POWERTRAIN CONTROL MODULE PPL PPL PPL RED WIRE RWAL DIODE MODULE (UNDER LEFT SIDE OF I/P) TRANSFER CASE MODE SELECTOR ILLUMINATION LAMP (AT TRANSFER CASE SELECTOR LEVER) TRANSFER CASE RELAY (RIGHT REAR OF ENG COMPT, NEAR BATTERY JUNCTION BLOCK) TRANSFER CASE SWITCH (LEFT TOP OF TRANSFER CASE) TRANSFER CASE SYNCRONIZER