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.
BCM Overview
The body control module (BCM) is a integrated module that combines functions and features from a normal control module and an body electrical center. There are 4 electrical interfaces that exist between the BCM and the rest of the vehicle. There are 2 connections from the BCM to both the body wiring harness and the instrument panel wiring harness. The BCM contains fuses and relays that are serviceable.
The main features of the BCM are:
- The BCM is the gateway between class 2 serial data circuit and high speed GMLAN serial data circuit.
- The BCM controls multiple functions.
- The BCM controls electrical power management.
- The BCM is the power mode master.
Use the Manual With the Right Hardware
Pair factory procedures with proven DIY tools so the instructions are easier to execute.
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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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