Heated Glass Element Switch: Description and Operation

Fig.3 HVAC Control Panel:

The rear window defogger switch is integrated into the HVAC control panel assembly

A LED indicator will illuminate when the switch is activated. The switch energizes the HVAC control assembly when it requests the Front Control Module (FCM) to activate the rear window defogger relay The relay controls the current to flow to the grids of the rear window defogger, heated power side view mirrors and the heated windshield wiper de-icer. The defogger relay will be ON for approximately 10 minutes or until the control switch or ignition is turned OFF.