Rear Defogger System Components
The rear window defogger system consist of the following components:
| • | Instrument panel integration module (IPM) |
| • | Rear integration module (RIM) |
| • | RR DEFOG relay |
| • | Rear window defogger grid |
Rear Window Defogger Operation
Battery positive voltage is supplied through the RR DEFOG fuse to the RR DEFOG relay switched input. Ignition voltage is supplied to the RR DEFOG relay coil. When you turn the ignition to the ON position, and depress the rear window defogger switch. The IPM sends a class 2 message to the RIM to enable the rear window defogger system, the RIM energizes the RR DEFOG relay by grounding the control circuit of the relay. This allows battery positive voltage from the relay switched input through the switch contacts and out the relay switched output to the rear window defogger. The RIM then sends a class 2 message to the IPM requesting the illumination of the rear window defogger indicator. The IPM illuminates the rear window defogger indicator. Ground for the rear window defogger is provided by G304.
When you turn ON the ignition and press the rear window defogger switch for the first time, the defogger cycle lasts 10 minutes. Further operation results in 5 minute defogger cycles. The defogger cycle resets to 10 minutes when you cycle the ignition to the OFF position and then back to the ON position.
If the battery voltage is very low, the rear defogger feature is disabled.
