Heated Glass Element: Description and Operation

Rear Window Defogger:

REAR WINDOW DEFOGGER SYSTEM
For proper operation of the Rear Window Defogger system, refer to the Owner's Manual.

The system consists of a rear glass with two vertical bus bars and a series of electrically connected grid lines on the inside surface. The control switch is located in the HVAC Control Module, in the center of the Mode Control knob. The rear window defogger relay is in the Micro Relay Bank which is located behind and above the glove box. The timer is located in the Body Control Module (BCM).

Circuit protection for heated grid is provided by:
- Fuse 12 (EBL) located in the Power Distribution Center.
- Rear window defogger relay (EBL) located in the Micro Relay Bank.

The input for the rear window defogger is included in the signal from the HVAC control over the A/C mode switch MUX circuit. Press this button once to turn ON the Rear Window Defogger and a second time to turn it OFF. A LED in the button shows that the defogger is ON. The defogger turns OFF automatically after 10 minutes of operation. Each later activation will allow 5 minutes of operation. The timer functions for the rear window defogger are controlled by the BCM.

When the button is depressed to the ON position, current is directed to the rear defogger grid lines. A yellow indicator within the center of the button will illuminate while the defogger is ON. The heated grid lines will heat the rear glass and clear the window surface of fog or frost.

CAUTION: Grid lines can be damaged or scraped off with sharp instruments, care should be taken in cleaning glass or removing foreign materials, decals or stickers. Normal glass cleaning solvents or hot water used with rags or toweling is recommended.

HVAC Control Module:

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 10 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.