Heated Element: Description and Operation

How the Circuit Works

Rear Window Defogger

Battery voltage is supplied at all times to the Rear Window Defogger Relay contacts through fuse 4 (Under-hood). With the ignition switch in ON (II), battery voltage is supplied to the Rear Window Defogger Relay coil and to the HVAC Control Unit or Climate Control Unit through fuse 16 (in the driver's under-dash fuse/relay box).

When the Rear Window/Power Mirror Defoggers Switch (in the HVAC Control Unit, the Climate Control Unit, or the Front Passenger's Climate Control Switch) is pressed, the defog signal is sent to the Driver's MICU. The Driver's MICU provides ground to the Rear Window Defogger Relay coil, energizing the relay. Battery voltage is supplied to the Rear Window Defogger through the energized relay.

The Rear Window Defogger is turned off by pressing the Rear Window/Power Mirror Defoggers Switch a second time of by turning the ignition switch to LOCK (0).

Power Mirror Defoggers

Battery voltage is supplied at all times to the Front Passenger's Power Window Switch through fuse 13 (in the passenger's under-dash fuse/relay box). With the ignition switch in ON (II), battery voltage is supplied to the Power Window Mirror Switch and to the HVAC Control Unit or Climate Control Unit through fuse 16 (in the driver's under-dash fuse/relay box).

When the Rear Window/Power Mirror Defoggers Switch (in the HVAC Control Unit, the Climate Control Unit, or the Front Passenger's Climate Control Switch) is pressed, the defog signal is sent to the Power Window Master Switch via B-CAN and then to the Front Passenger's Power Window Switch via UART. The Power Window Master Switch supplies battery voltage to the Left Power Mirror Defogger and the Front Passenger's Power Window Switch supplies battery voltage to the Right Power Mirror Defogger.

The Power Mirror Defoggers are turned off by pressing the Rear Window/Power Mirror Defoggers Switch a second time of by turning the ignition switch to LOCK (0).