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: Notes
Located behind the glove box, the Body Control Module (BCM) contains a microprocessor which provides central control over all system switches and sensors. Based on inputs and program instructions contained within BCM memory, the computer calculates the proper outputs for accurate operation of climate control system. The BCM and the Electronic Control Module (ECM) communicate over a data link to share sensor information. The ECM is also used to control functions such as compressor clutch engagement.
The BCM is also equipped with a self-diagnostic function. By depressing the appropriate buttons on the climate control panel, data messages can be sent to BCM, requesting the specific diagnostic features required. If a fault is detected in the system, a trouble code is set in the BCM memory. By following specific testing procedures, system diagnosis should determine faulty component in the shortest time period.
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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.