Buick LaCrosse I (2004-2009) (in back of right headlamp on frame) Wiring diagrams

A/C CLU DIODE A/C CLUTCH FUSE 13 A/C COMP RELAY 38 A/C COMPRESSOR CLUTCH SOLENOID A/C COMPRESSOR TEMPERATURE SWITCH A/C REQUEST IND A/C REQUEST SWITCH AIR TEMP A AIR TEMP B AIR TEMP A AIR TEMP B AUTO OFF BLOWER MOTOR SW BATTERY IGN 1 VOLT CLASS 2 SERIAL BLK WIRE BLK/WHT WIRE BRN WIRE COMPUTER DATA LINES SYSTEM 8 1450 734 720 INTERIOR LIGHTS SYSTEM DEFOGGER IND DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE FAN 1 FUSE 29 FAN 1 RELAY 42 FAN 2 FUSE 32 FAN 2 RELAY 46 FAN 3 RELAY 43 GROUND GRY WIRE GRY/BLK WIRE HIGH LOW HOT AT ALL TIMES HOT IN RUN OR START HVAC CONTROL MODULE (CENTER OF DASH) ILLUM LOGIC LOWER LEFT AIR TEMPERATURE SENSOR (BEHIND HVAC CONTROL MODULE) LOWER RIGHT AIR TEMPERATURE SENSOR (BEHIND HVAC CONTROL MODULE) LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MODE ACTUATOR (LOWER LEFT SIDE OF HVAC ASSEMBLY) MODE DOOR A MODE DOOR B MODE SWITCH NCA WIRE ORG/ WIRE ORG/BLK WIRE PNK WIRE PNK/WHT WIRE PPL REAR DEFOGGER SWITCH RECIRATION A RECIRATION B RECIRCULATION ACTUATOR (NEAR RIGHT "A" PILLAR, ON UPPER HVAC CASE) RECIRCULATION IND RECIRCULATION SWITCH SENSOR SIG SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG SENSOR SIG LOW REF PPL SPEED CTRL TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TEMPERATURE CONTROL SW UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WHT WIRE WHT/BLK WIRE YEL WIRE

23 7 ECT SENS SIG LOW REF 4 20 48 HI SPD FAN RLY LO SPD FAN RLY CLASS 2 SERIAL BLK WIRE COMPUTER DATA LINES SYSTEM DK BLU WIRE DK GRN WIRE ENGINE CONTROL MODULE (ECM) (TOP OF ENGINE) FAN 1 FUSE 29 FAN 1 RELAY 42 FAN 2 FUSE 32 FAN 2 RELAY 46 FAN 3 RELAY 43 GRY WIRE HOT AT ALL TIMES LEFT COOLING FAN MOTOR (ON LEFT SIDE OF RADIATOR) LT BLU WIRE RIGHT COOLING FAN MOTOR (ON RIGHT SIDE OF RADIATOR) TAN WIRE UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WHT WIRE YEL WIRE

12 13 14 15 16 PPL 8 1450 734 720 INTERIOR LIGHTS SYSTEM A/C CLU DIODE A/C CLUTCH FUSE 13 A/C COMP RELAY 38 AUTO OFF BLOWER MOTOR SW BATTERY IGN 1 VOLT CLASS 2 SERIAL BLK WIRE BLK/WHT WIRE BRN WIRE COMPUTER DATA LINES SYSTEM DEFOGGER IND DK BLU WIRE DK BLU/WHT WIRE DK GRN WIRE DK GRN/WHT WIRE FAN 1 FUSE 29 FAN 1 RELAY 42 FAN 2 FUSE 32 FAN 2 RELAY 46 FAN 3 RELAY 43 GROUND GRY WIRE GRY/BLK WIRE HIGH LOW HOT AT ALL TIMES HOT IN RUN OR START HVAC CONTROL MODULE (CENTER OF DASH) ILLUM LOGIC LOWER LEFT AIR TEMPERATURE SENSOR (BEHIND HVAC CONTROL MODULE) LOWER RIGHT AIR TEMPERATURE SENSOR (BEHIND HVAC CONTROL MODULE) LT BLU WIRE LT BLU/BLK WIRE LT GRN WIRE LT GRN/BLK WIRE MODE ACTUATOR (LOWER LEFT SIDE OF HVAC ASSEMBLY) MODE SWITCH ORG/ WIRE ORG/BLK WIRE PNK WIRE PNK/WHT WIRE REAR DEFOGGER SWITCH RECIRCULATION ACTUATOR (NEAR RIGHT "A" PILLAR, ON UPPER HVAC CASE) RECIRCULATION IND RECIRCULATION SWITCH REQUEST SWITCH A/C A/C REQUEST IND SENSOR SIG SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG LOW REF SENSOR SIG SENSOR SIG LOW REF PPL SPEED CTRL TAN WIRE TAN/BLK WIRE TAN/WHT WIRE TEMPERATURE CONTROL SW UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WHT WIRE WHT/BLK WIRE YEL WIRE

50 48 15 HI SPD FAN RLY LO SPD FAN RLY CLASS 2 SERIAL 55 29 ECT SENS SIG LOW REF BLK WIRE COMPUTER DATA LINES SYSTEM DK BLU WIRE DK GRN WIRE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (ON TOP RIGHT OF INTAKE MANIFOLD) FAN 1 FUSE 29 FAN 1 RELAY 42 FAN 2 FUSE 32 FAN 2 RELAY 46 FAN 3 RELAY 43 GRY WIRE HOT AT ALL TIMES LEFT COOLING FAN MOTOR (ON LEFT SIDE OF RADIATOR) LT BLU WIRE RIGHT COOLING FAN MOTOR (ON RIGHT SIDE OF RADIATOR) UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WHT WIRE YEL WIRE

380 2700 2751 473 335 1049 31 4 7 50 48 15 33 A/C PRESS SIGNAL 55 29 410 2761 ECT SENS SIG LOW REF A/C CLU DIODE A/C CLUTCH FUSE 13 A/C COMP RELAY A/C REFRIGERANT PRESSURE SENSOR (ON LEFT SIDE OF ENGINE COMPT, ON ACCUMULATOR) A/C REQUEST IND A/C REQUEST SWITCH AIR TEMP B AIR TEMP A RECIRCULATION B RECIRCULATION A AIR TEMPERATURE ACTUATOR (RIGHT SIDE OF HVAC ASSEMBLY) BATT MAIN 4 FUSE 30 BATTERY IGNITION 1 BLK WIRE BLK/WHT WIRE BLOWER MOTOR (BEHIND RIGHT SIDE OF DASH, IN HVAC MODULE) BLOWER MOTOR CONTROL PROCESSOR (ON LOWER RIGHT SIDE OF DASH) BREAKOUT TO DATA LINK CONNECTOR TOWARDS BRAKE PEDAL POSITION SENSOR) CLASS 2 SERIAL COMPUTER DATA LINES SYSTEM DEFOGGER IND REAR DEFOGGER SWITCH DISPLAY FUSE 18 DK BLU WIRE DK GRN WIRE DK GRN/WHT WIRE ENGINE COOLANT TEMPERATURE (ECT) SENSOR (ON TOP RIGHT OF INTAKE MANIFOLD) FAN 1 FUSE 29 FAN 1 RELAY 42 FAN 2 FUSE 32 FAN 2 RELAY 46 FAN 3 RELAY 43 GROUND GRY WIRE GRY/BLK WIRE HARNESS, APPROXI- MATELY 20 CM FROM HIGH LOW HOT AT ALL TIMES HOT AT ALL TIMES I/P FUSE BLOCK HVAC FUSE (BEHIND RIGHT SIDE OF DASH) HOT IN RUN OR START HVAC CONTROL MODULE (CENTER OF DASH) ILLUM ILLUM INTERIOR 8 1450 LIGHTS SYSTEM LEFT COOLING FAN MOTOR (ON LEFT SIDE OF RADIATOR) LOGIC LOW REF HIGH SPD COOLING LOW SPD COOLING CLASS 2 SERIAL A/C COMP CLUTCH LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE MODE ACTUATOR (LOWER LEFT SIDE OF HVAC ASSEMBLY) MODE SWITCH OFF BLOWER MOTOR SW ORG/ WIRE PNK WIRE PNK/WHT WIRE PPL PPL SUPPLY GND BATTERY SPEED CTRL GND RECIRCULATION ACTUATOR (NEAR RIGHT "A" PILLAR, ON UPPER HVAC CASE) RECIRCULATION IND RECIRCULATION SWITCH RED WIRE RED/BLK WIRE RIGHT COOLING FAN MOTOR (ON RIGHT SIDE OF RADIATOR) RIGHT STRUT TOWER) SPEED CTRL MODE DOOR B MODE DOOR A TAN WIRE TEMPERATURE CONTROL SW TOWARDS BRAKE PEDAL POSITION SENSOR) UNDERHOOD FUSE BLOCK (MOUNTED TO WHT WIRE YEL WIRE

30 48 43 STOP LAMP SW SIG RR STOP/TURN VOLT LR STOP/TURN VOLT 8 16 17 4 PARK LAMP ON SIG HAZARD SW SIG RIGHT TURN SW SIG LEFT TURN SW SIG ANTI-LOCK BRAKES, ENGINE CONTROLS SYSTEM ANTI-LOCK BRAKES, ENGINE CONTROLS, TRANSMISSIONS SYSTEMS BCM CLASS 2 SERIAL DATA BCM CLASS 2 SERIAL DATA IGN BLK WIRE BLK/WHT WIRE BLU WIRE BODY CONTROL MODULE (BCM) (BELOW LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) BRN WIRE BRN/WHT WIRE CENTER HIGH MOUNTED STOP LAMP (CHMSL) CHMSL/ BKUP FUSE COMPUTER DATA LINES SYSTEM DK BLU/WHT WIRE DK GRN WIRE DK LT DRIVER INFORMATION CENTER GRY WIRE HAZARD HAZRD FUSE HEAD HOT AT ALL TIMES HOT AT ALL TIMES I/P FUSE BLOCK (BEHIND RIGHT SIDE OF DASH) IGN INSTRUMENT PANEL CLUSTER (IPC) IPC CLASS 2 SERIAL DATA LAMP SWITCH ASSEMBLY LEFT LEFT FRONT MARKER LAMP LEFT FRONT PARK/ TURN SIGNAL LAMP LEFT LICENSE LAMP LEFT TAIL/ STOP, TURN SIGNAL LAMP LEFT REAR LEFT TURN INDICATOR LOGIC LOWER UPPER LEFT LEFT TAIL LAMP TAIL LAMP LT BLU WIRE LT BLU/WHT WIRE LT GRN WIRE MARKER LAMP ORG/ WIRE PARK AUTO OFF PRK LAMP FUSE PRK LAMP RELAY RIGHT RIGHT FRONT MARKER LAMP RIGHT FRONT PARK/ TURN SIGNAL LAMP RIGHT LICENSE LAMP RIGHT REAR RIGHT TAIL/ STOP, TURN SIGNAL LAMP LOWER RIGHT TAIL LAMP UPPER RIGHT TAIL LAMP RIGHT TURN INDICATOR SPLICE PACK TAN WIRE TURN AUDIBLE INDICATOR TURN SIGNAL/ MULTI-FUNCTION SWITCH WHT WIRE YEL WIRE

3.6L 3.8L A/C CLU DIODE A/C COMPRESSOR CLUTCH A/C WIPER RELAY 37 RELAY 45 AUTOMATIC TRANSMISSION TRANSMISSION CLUTCH INTERNAL MODE DIODE SWITCH (IMS) BATTERY BLK WIRE BODY CONTROL MODULE (BCM) ELECTRONIC BRAKE CONTROL MODULE (EBCM) EXCEPT SULEV FUEL PP RELAY 41 HEADLAMP ASSEMBLY) HOOD AJAR SWITCH HORN ASSEMBLY IGN 1 HDM BEAM MODULE 35 IGN 1 HDM BEAM RELAY 37 MODULE 35 LAMP LEFT FRONT MARKER LAMP LEFT HIGH BEAM HEADLAMP POWERTRAIN CONTROL MODULE (PCM) RIGHT COOLING FAN RIGHT FRONT MARKER LAMP RIGHT FRONT PARK/ RIGHT TURN FRONT SIGNAL FOG LAMP LAMP RIGHT HIGH BEAM HEADLAMP SECONDARY AIR INJECTION (AIR) PUMP (SULEV) SULEV TAN WIRE THROTTLE ACTUATOR CONTROL (TAC) MODULE TRANSMISSION CONTROL MODULE (TCM) FUEL PP RELAY 41 WHT WIRE WINDSHIELD WASHER FLUID LEVEL SWITCH WINDSHIELD WASHER FLUID PUMP

3.6L 3.8L AMBIENT SUNLOAD LIGHT SENSOR SENSOR ASSEMBLY (TOP OF (TOP CENTER OF DASH) DASH) AUTO PARK BCM BCM CLASS 2 SERIAL BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) BRN WIRE CLSTR FUSE COMPUTER DATA LINES SYSTEM DK GRN WIRE DK GRN/WHT WIRE DRL AMBIENT LIGHT EXTERIOR LAMPS OFF FLASH TO PASS SW FOG FOG LAMP IND FOG LAMP RELAY CTRL FOG LP RELAY 36 FOG LPS FUSE 7 FRONT FOG LAMP SW FTP GRY WIRE HDLP SUGGEST IND HDM BEAM MODULE 35 HEAD HEADLAMP MOD CTRL HEADLAMP ON SIG HI BEAM RELAY 34 HI BEAM RLY CTRL HIGH BEAM IND HOT AT ALL TIMES I/P FUSE BLOCK (BEHIND RIGHT SIDE OF DASH) IGN IGN B+ INSTRUMENT PANEL CLUSTER (IPC) LAMP SWITCH ASSEMBLY LEFT FRONT FOG LAMP LEFT HIGH BEAM HEADLAMP LEFT LOW BEAM HEADLAMP LF HI BEAM FUSE 1 LF LO BEAM FUSE 3 LOGIC LT BLU WIRE LT GRN WIRE LT GRN/BLK WIRE MANUAL AUTO A/C A/C OFF ORG/ WIRE PNK WIRE PNK/WHT WIRE PPL PPL HEADLAMP DIMMER SW RF HI BEAM FUSE 2 RF LO BEAM FUSE 4 RIGHT FRONT FOG LAMP RIGHT HEADLAMP ON FRAME) RIGHT HIGH BEAM HEADLAMP RIGHT LOW BEAM HEADLAMP SERIAL DATA TAN WIRE TURN SIGNAL/ MULTIFUNCTION SWITCH UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WHT WIRE YEL WIRE

BLK WIRE BODY CONTROL MODULE (BCM) (BEHIND LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) DK GRN WIRE GROUND DISTRIBUTION SYSTEM HORN ASSEMBLY (RIGHT FRONT OF VEHICLE) HORN FUSE 11 HORN RELAY 39 HORN RLY CTRL HORN SWITCH HOT AT ALL TIMES INFLATABLE RESTRAINT STEERING WHEEL MODULE COIL (IN STEERING COLUMN) NCA WIRE STEERING WHEEL) TAN WIRE UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER)

3.6L 3.8L BATTERY BLK WIRE BLK/WHT WIRE BODY CONTROL MODULE (BCM) (BEHIND LEFT SIDE OF DASH, LEFT OF STEERING COLUMN) CLASS 2 SERIAL DATA DELAY SWITCH DK GRN WIRE GRN WIRE GROUND GRY WIRE HIGH PPL HOT AT ALL TIMES IGN LOGIC INSTRUMENT PANEL CLUSTER (IPC) LOW WASH INDICATOR LOW WASHER FLUID IND SIG LT BLU WIRE LT GRN WIRE MESSAGE CENTER LOW WASHER FLUID MESSAGE REQUEST MIST OFF ORG/ WIRE PARK SW SIG PARK SWITCH PNK WINDSHIELD WASHER SW SIG WIRE PNK WIRE PPL DK RED WIRE SPLICE PACK TAN WIRE TURN SIGNAL/ MULTIFUNCTION SWITCH UNDERHOOD FUSE BLOCK (MOUNTED TO RIGHT STRUT TOWER) WASHER PUMP CTRL WASHER SWITCH WASHER/ RVC FUSE 6 WHT WIRE WINDSHIELD WASHER FLUID LEVEL SWITCH WINDSHIELD WIPER MOTOR (ON LEFT SIDE OF FIREWALL) WINDSHIELD WIPER SW HI SIG WINDSHIELD WIPER SW HIGH SIG WINDSHIELD WIPER SW LOW SIG WINDSHIELD WIPER SWITCH WIPER HI RELAY 44 WIPER RELAY 45 WIPER RLY CTRL WIPER/ WS FUSE 5 YEL WIRE