Heated Glass Element: Description and Operation

When the Ignition Switch is turned to RUN, voltage is applied from the HVAC/DRL Fuse (CKT 241) to the Rear Window Defogger Relay and the Heater-A/C Control. The Rear Window Defogger Relay also receives battery voltage from the RR DEFOG Fuse (CKT 1040). When the Rear Defogger Switch is pressed, ground is applied to the solid state timer in the Heater-A/C Control, sending a voltage signal (CKT 193) to the Rear Window Defogger Relay. The solenoid within the Rear Window Defogger Relay is energized pulling the switch within the Rear Window Defogger Relay closed. When this switch is closed voltage is supplied to the Rear Defogger Grid through CKT 293. The switch will remain closed until the defog cycle is complete or the Rear Defogger Switch is pressed a second time.

When the Ignition Switch is turned to RUN and the Rear Defogger Switch pressed for the first time, the defog cycle lasts 10 minutes and further operation will result in 5 minute defog cycles. The defog cycle is reset to 10 minutes when the Ignition Switch is turned to LOCK and back to RUN.

The Defogger ON Indicator is an LED that illuminates when the Rear Defogger is ON. This LED will be step dimmed by the LED Indicator Control when the Park Lamps are turned ON.