Body Control Module: Operation

The Body Control Module is designed to control and integrate many of the electronic features and functions of the vehicle. The microprocessor-based Body Control Module hardware and software monitors many hardwired switch and sensor inputs as well as those resources it shares with other electronic modules in the vehicle through its communication over the Controller Area Network (CAN) Bus. The internal programming of the Body Control Module microprocessor allows the Body Control Module to determine the tasks it needs to perform and their priorities. The Body Control Module programming then performs those tasks and provides features through both CAN Bus communication with other electronic modules and hardwired outputs to a number of relays. These relays provide the Body Control Module with the ability to control numerous high current accessory systems in the vehicle.

The Body Control Module circuitry operates on battery current received through fuses in the Underhood Accessory Fuse Block on a non-switched fused B(+) circuit, a fused ignition switch output (start-on/run) circuit, and a fused ignition switch output (start-on/run-accessory) circuit. This arrangement allows the Body Control Module to provide some features regardless of the ignition switch position. The Body Control Module circuitry is grounded through the chassis behind the right side lower A-pillar kick panel.

The Body Control Module monitors its own internal circuitry as well as many of its input and output circuits and will store a Diagnostic Trouble Code (DTC) in electronic memory for any failure it detects. These DTCs can be retrieved and diagnosed using a DRB III(R) scan tool. Refer to ELECTRONIC CONTROL MODULES - ELECTRICAL DIAGNOSTICS .