Heated Glass Element: Description and Operation

With the Ignition Switch in RUN, power is applied through the 687 (GY/Y) and 298 (P/O) wires to the Rear Window Defrost Window Defrost Switch.

Pressing the Rear Window Defrost Switch ON closes the contacts of the defrost relay and starts the ten minute (approximate) timing cycle. Current now flows to the Rear Window Defrost Grid. When the Rear Window Defrost Switch is released from ON, the solid-state circuitry keeps the defrost relay coil energized.

Pressing the Rear Window Defrost Switch OFF deenergizes the defrost relay, removing power from the defrost circuit.

If the OFF switch is not pressed, power remains on until the time delay runs out. The coil then deenergizes and removes power from the defrost circuit.