Heated Glass Element Switch: Description and Operation

The switch for the rear window defogger (EBL) system (1) is integrated into the A/C-heater control (2), which is located in the center of the instrument panel. When the rear window defogger switch is pressed to On position a request signal is sent on the CAN-B Bus to the totally integrated power module (TIPM) to operate the EBL system.

When the high side driver in the totally integrated power module (TIPM) is energized, current is directed to the rear defogger grid lines and to the heated side view mirrors. The grid lines heat the glass to help clear the surface of fog or frost.

An amber indicator will illuminate when the rear window defogger switch is activated. When activated, the switch sends a request signal to the to the totally integrated power module (TIPM) to energize the internal EBL high side driver to provide battery current to the rear window defogger grid lines and to the heated side view mirrors.

NOTE: The EBL system turns off automatically after 15 minutes of initial operation. Each following activation cycle of the EBL system will last 10 minutes.

The EBL system will be automatically turned off after an initial programmed time interval of about 15 minutes as long as the ignition switch is the Run position. After the initial time interval has expired, if the rear window defogger switch is turned on again during the same ignition cycle, the EBL system will automatically turn off after about 10 minutes. The EBL system will automatically shut off if the ignition switch is turned to any position other than Run, or it can be turned off manually by pressing the rear window defogger switch a second time.

The rear window defogger switch is diagnosed using a scan tool.

The rear window defogger switch and the rear window defogger indicator cannot be repaired and, if faulty or damaged, the A/C-heater control must be replaced.