BCM Module
At the heart of the BCM/ECM computer system, is the Body Computer Module (BCM). The BCM is located in the middle of the instrument panel, behind the Climate Control/Driver Information Center (CCDIC). See Fig 1 .
The BCM has an internal microprocessor which links the BCM with all other components in the system. All system sensors and switches are monitored by the BCM or one of 4 major components that complete the BCM/ECM computer system.
In order to control and access the self-diagnostic features available to the BCM, 4 additional electronic components are utilized: the Engine Control Module (ECM), the Instrument Panel Cluster (IPC), the Heating Ventilation and A/C (HAVC) programmer, and the (CCDIC).
A combination of inputs from these 4 major components and other sensors and switches communicate with the BCM. The data communication gives the BCM control over the ECM's self-diagnostic capabilities in addition to its own.