Heated Glass Element: Description and Operation

When the Ignition Switch is turned to "RUN," voltage is applied through the IGN Fuse to the Rear Window Defog Switch in the Heater-A/C Control. A solid state timer in the Rear Window Defogger Relay controls battery voltage through the relay. When the Rear Window Defog Switch is pressed, voltage is momentarily applied to the timer, closing the Rear Window Defogger Relay contacts. Voltage from the Rear Defog Circuit Breaker is applied through the relay contacts to the Rear Window Defogger Grid and Indicator until the defog cycle is complete or the Rear Window DEFOG Switch is pressed a second time.

When the Ignition Switch is turned to "RUN" and the Rear Window Defogger Switch pressed for the first time, the defog cycle lasts 10 minutes and further operation results in 5 minutes defog cycles. The defog cycle is reset to 10 minutes when the Ignition Switch is turned to "OFF" and back to "RUN."