Heated Glass Element: Description and Operation

Circuit Operation
Voltage is applied at all times through the EB-16 MAIN fuse to the rear defogger relay coil. With the starter switch in ON, voltage is applied through the CB-16 REAR WIPER & WASHER fuse to the rear defogger relay contacts.

When you push the rear defogger switch to the ON position, battery voltage is applied from the CB-8 (MIRROR DEFOG.) fuse to the left and right power mirror defoggers. The power mirror defogger heats up to remove any fog from the mirrors.

When the rear window defogger switch is depressed, the ECM or PCM receives a ground input from the switch and, in turn, the ECM or PCM provides ground to the coils of the rear window defogger relay. The contacts close, applying ignition voltage to the rear window defogger, rear window defogger indicator light (through the CB-9 and CB-10 REAR DEFOG. Fuses), and the left and right power mirror defoggers (through the CB-8 MIRROR DEFOG. fuse). The ECM or PCM acts as the timer for the rear window defogger relay and keeps the contacts closed maintaining the operation of the rear window defogger, left and right mirror defoggers and indicator light for 10 minutes or until the ignition is turned to "ACC" or "OFF", or ate rear window defogger switch is depressed again. The rear window and mirrors heat to remove any fog from the glass and the indicator stays on to remind the driver that it is in use.