Theory Of Operation

WARNING: This page is about a different car, the 2024 RAM ProMaster EV. However, it is still accessible from the selected car via links, so may be relevant.

When equipped with Electric Backlite (EBL) rear window defrost and the heated mirror feature, the heated mirrors are activated when the EBL system is turned on. When the EBL system is activated, an electric grid located behind the glass of each outside rear view mirror becomes energized and produces heat to help clear the mirror surface of ice, snow, or fog. If the vehicle is not equipped with the EBL system, heated mirror operation turns on and off with the HVAC defrost switch.

If both outside mirror heating grids are inoperative, test the EBL system for proper operation.

When the Body Control Module (BCM) receives an input signal from the Rear Window Defogger switch or the HVAC module defrost request, the BCM provides a ground signal to the Rear Window Defogger relay, which activates the Rear Window Defogger and the Heated Rear View Mirrors.