GM Service Manual Online
For 1990-2009 cars only

BCM Scan Tool Data Definitions

The BCM Scan Tool Data Definitions contains a brief description of all Rear Window Defogger related BCM parameters available on the scan tool.

HVAC Rear Defogger Switch: The scan tool displays Active or Inactive. When the rear defogger switch is pressed, the scan tool will display Active. When the switch is released, the scan tool displays Inactive.

Rear Defogger Relay: The scan tool displays Active or Inactive. When the BCM energizes the rear defogger relay, the scan tool will display Active. When the BCM de-energizes the rear defogger relay, the scan tool will display Inactive.