Control Assembly: Description and Operation

HVAC Control Module:

Rear Window Defogger:

HVAC CONTROL MODULE
The rear window control switch and circuit are integrated into the HVAC control module.

When actuating the switch it sends a ground signal to the Body Control Module (BCM). The BCM actuates the relay allowing current to flow through the grid lines for ten minutes upon initial actuation. Then 5 minutes with each subsequent actuation or until either the switch or ignition is turned OFF. An indicating lamp illuminates the rear window defogger switch.