Heated Glass Element: Description and Operation

When the Rear Defogger Switch is pressed, voltage is applied to the solid state Timing Circuit and the ON indicator. The Timing Circuit grounds circuit 193 which energizes the Rear Defogger Relay to close the relay switch contacts. This applies voltage to circuit 293 and the Rear Defogger Grid. The rear window becomes warm to remove the condensation from the surface of the window.

The contacts in the Timing Circuit stay closed until the Rear Defogger Switch is pressed again. the timer cycle is complete, or the Ignition Switch is turned to the OFF position.

The first time the Rear Defogger Switch is pressed. he Timing Circuit allows the Rear Defogger to operate for approximately ten minutes. Each time after that when the Rear Defogger Control Switch is pressed, the Timing Circuit operates for approximately five minutes. The Timing Circuit resets to ten minutes when the Ignition Switch is turned to the OFF position.