Heated Glass Element: Description and Operation

Circuit Operation
Rear Window Defogger System Components The rear window defogger system consist of the following components:
- HVAC control module
- Liftgate module (LGM)
- Rear window defogger grid

Rear Window Defogger Operation
Battery positive voltage is supplied through the LGM 2 fuse to the LGM for the rear window defogger system. When you turn the ignition to the ON position, and the rear window defogger switch is depressed. The HVAC control module illuminates the rear window defogger indicator and sends a class 2 message to the LGM to enable the rear window defogger system. The LGM enable the rear window defogger system by allowing battery positive voltage to the rear window defogger. When you turn ON the ignition and press the rear window defogger switch for the first time, the defogger cycle lasts 10 minutes. Further operation results in 10 minute defogger cycles.