Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Body Control Module
The various body control module (BCM) input and output circuits are described in the corresponding functional areas indicated on the BCM electrical schematics. The BCM functions include the following:
- A/C compressor request - Refer to Air Temperature Description and Operation in HVAC Systems - Manual.
- A/C cooling fan - Refer to Air Delivery Description and Operation in HVAC Systems - Manual.
- Battery rundown protection (inadvertent power) - Refer to Interior Lighting Systems Description and Operation in Lighting Systems.
- Bulb check - Refer to Instrument Panel Cluster (IPC) Description and Operation in Instrument Panel, Gages, and Console.
- Chimes - Refer to Indicator/Warning Message Description and Operation
in Instrument Panel, Gages, and Console.
- Check gages
- Door ajar warning
- Headlamps ON
- Key-in-ignition
- Oil reset
- Park brake warning
- Seat belt not fastened
- Turn signal ON
- Door lock interface - Refer to Power Door Locks Description and Operation in Doors.
- Electronic power steering (EPS) - Refer to Power Steering System Description and Operation in Power Steering System.
- Engine coolant level sensing - Refer to Cooling System Description and Operation in Engine Cooling.
- Exterior and interior lighting control - Refer to Exterior Lighting Systems Description and Operation
in Lighting Systems.
- Automatic lighting control
- Daytime running lamps (DRL)
- Fog lamps
- Park brake lights
- Turn hazard lamps
- Gage control - Refer to Instrument Panel Cluster (IPC) Description and Operation in Instrument Panel, Gages, and Console.
- Horn interface - Refer to Horns System Description and Operation in Horns.
- Instrument cluster indicator control - Refer to Instrument Panel Cluster (IPC) Description and Operation in Instrument Panel, Gages, and Console.
- Interior lighting - Refer to Interior Lighting Systems Description and Operation in Lighting Systems.
- Key-in-ignition sensing - Refer to Indicator/Warning Message Description and Operation in Instrument Panel, Gages, and Console.
- Parking brake state sensing - Refer to Brake Warning System Description and Operation in Hydraulic Brakes.
- Retained accessory power (RAP) - Refer to Retained Accessory Power (RAP) Description and Operation .
- Rear compartment interface - Refer to Power Door Locks Description and Operation in Doors.
- Rear defogger - Refer to Rear Window Defogger Description and Operation in Stationary Windows.
- Remote function control - Refer to Keyless Entry System Description and Operation in Keyless Entry.
- Seat belt use sensing - Refer to Seat Belt System Description and Operation in Seat Belts.
- Content theft deterrent - Refer to Theft Systems Description and Operation in Theft Deterrent.
- Vehicle theft deterrent - Refer to Vehicle Theft Deterrent (VTD) Description and Operation in Theft Deterrent.
- Washer solvent level sensing - Refer to Wiper/Washer System Description and Operation in Wipers/Washer Systems.
- Wiper/washer - Refer to Wiper/Washer System Description and Operation in Wipers/Washer Systems.
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.
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