Windows and Glass: Description and Operation
Voltage is applied at all times through fuse 22 to the rear window defogger relay. With the ignition switch in ON (II), voltage is applied through fuse 8 to the rear window defogger relay and the defogger ON indicator.When you push the defogger switch once, a path to ground is provided for the rear window defogger relay and the defogger ON indicator through the integrated control unit. The defogger ON indicator light comes ON and the rear window relay contacts close. Voltage is applied to the defogger grid on the inside surface of the rear window, and the grid heats the rear window to remove any fog from the glass.
You can turn the defogger OFF by pushing the switch a second time or by turning the ignition switch to LOCK (0). A timer in the integrated control unit will automatically turn the defogger OFF after it has been ON continuously for 20 to 30 minutes.