Heated Glass Element: Description and Operation

The Rear Defogger operates when voltage is applied to the grid lines inside the rear window surface. The grid lines heat the back window to remove interior fog from the glass. At the same time, voltage is applied to the heated mirror resistive wiring, heating the RH and LH rearview mirrors to remove fog from the surface.

When the Ignition Switch is in RUN, voltage is applied: 1) through I/P Fuse Block Fuse 7 and Defogger Relay coil to the ECC Programmer; and 2) through Circuit Breaker 24 to the Defogger Relay contacts.

When the Rear DEF Switch on the Climate Control Panel (CCP) is pushed, the Body Computer Module (BCM) signals the ECC Programmer to ground the Defogger Relay coil. The relay operates and current flows through the relay contacts Rear Defogger and heated mirrors to ground. The Rear Defogger and heated mirrors become warm.

The BCM controls the Rear Defogger circuit's timing. After 10 minutes, the BCM signals the ECC Programmer to break the circuit. Each time the Rear Defogger is turned on after that, the BCM signals the Rear Defogger to operate for 5 minutes. The BCM resets control timing to 10 minutes when the Ignition Switch is turned to OFF and then back to RUN.