Heated Element: Description and Operation

With Rear Defogger
Voltage is applied at all times through the EB-19 IGN. B2 fuse, to the rear window defogger relay coil. With the starter switch in ON, voltage is applied through the CB-16 (REAR WIPER WASHER) fuse to the rear window defogger relay contacts.

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 & 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 the 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.

Without Rear Defogger
With the starter switch in ON, voltage is applied through the CB-8 (MIRROR DEFOG.) fuse to the mirror defogger switch. When you press the mirror defogger switch to the ON position, ignition voltage is applied to the left and right power mirror defoggers and the defogger indicator light. The mirrors heat to remove any fog from the glass and the indicator comes on to remind the driver that it is in use.