Rear Window Defogger

The Body Control Module (BCM) controls the operation of the Rear Defogger Relay located in the Junction Block. The BCM will energize the relay when it receives a request from the HVAC control head (PCI bus message for Automatic Temperature Control or a MUX input for Manual Temp Control).

With the relay activated, it will supply battery voltage to the rear window defogger grid along with heat mirrors if so equipped.