Body Control Module (BCM) C60 C68

Battery Voltage Signal: The scan tool displays the vehicle voltage.

Rear Defog Relay Cmd.: The scan tool displays On/Off. When the rear window defogger switch is depressed, the body control module (BCM) energizes the Rear Window Defogger relay by suppling a B+ to the control circuit of the relay, when the scan tool displays as On.

Rear Defog Switch: The scan tool displays Off /On. When the rear window defogger switch is depressed, the HVAC control module sends a message over Low Speed GMLAN to the BCM. When the switch is depressed the scan tool will display On.