In a Buick automobile, the Body Control Module (BCM) is a computer that regulates and keeps track of a number of electronic systems and parts, including lighting, power windows and locks, and climate control.

To organize the functioning of various systems, the BCM communicates with the vehicle's other electronic control modules, such as the Powertrain Control Module (PCM). To modify the engine idle speed according to whether the air conditioning system is on or off, for instance, the BCM and PCM may exchange information.

A mechanic can use a specialized scanner to detect the diagnostic trouble codes kept in the BCM to help determine the cause of any issues. The BCM may also manage additional safety systems in the vehicle, including