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.