Rear Window Defogger System Components
The rear window defogger system consists of the following components:
| • | HVAC control assembly |
| • | RR DEFOG relay |
| • | Rear window that has a number of grid lines |
Rear Window Defogger Operation
Battery positive voltage is supplied through the RR DEFOG fuse in the underhood fuse block to the RR DEFOG relay switched input. Ignition voltage is supplied through the HTR-A/C fuse to the HVAC control assembly and the RR DEFOG relay coil. When the rear window defogger switch is depressed, the HVAC control assembly illuminates the rear window defogger indicator and supplies ground to the control circuit of the RR DEFOG relay. This energizes the RR DEFOG relay and allows battery positive voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger grid. Ground for the rear window defogger is provided by G402.
When the rear window defogger switch is depressed for the first time, the defogger cycle lasts for 10 minutes. Further operation results in 5 minute defogger cycles. The defogger cycle resets to 10 minutes when the ignition is cycled to the OFF position and then back to the ON position.
