Power Mirror Defoggers

Circuit Operation

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 C-16 (RR WIPER) fuse to the rear window defogger relay contacts.

When the rear window defogger switch is depressed, the ECM receives a ground input from the switch and, in turn, the ECM 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 lamp (through the C-9 & C-10 (REAR DEFOG.) fuses), and the left and right power mirror defoggers (through the C-8 (MIRROR DEFOG.) fuse). The ECM 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 lamp 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.