Heated Glass Element Switch: Description and Operation

The rear window defogger switch is integral to the heater-A/C control assembly, which includes the rear wiper and washer switches.

The rear window switch also contains the rear window defogger logic and timer circuitry, an amber defogger indicator lamp, the rear window defogger relay, and two switch illumination lamps. The indicator and illumination lamps in the switch pod use incandescent bulbs, which can be serviced.

The momentary-type rear window defogger switch provides a hard wired ground signal to the rear window defogger logic and timer circuitry, each time it is depressed.

The rear window defogger timer and logic circuitry responds by energizing or de-energizing the rear window defogger relay and the amber defogger indicator lamp, which lights to indicate when the defogger system is turned ON. Energizing the rear window defogger relay provides electrical current to the rear window defogger grid.

The rear window switch cannot be repaired. If any function of the switch except lighting is faulty or damaged, the entire heater-A/C control assembly must be replaced.