Rear Defogger System Components
The rear defogger system consist of the following components:
| • | HVAC control module (w/CJ2) |
| • | Instrument panel integration module (IPM) |
| • | Rear integration module (RIM) |
| • | Rear window defogger grid |
Rear Window Defogger Operation (w/CJ2)
Battery positive voltage is supplied through the RR DEFOG fuse, in the rear fuse block, 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 the rear window defogger switch is depressed. The HVAC control module sends a message via the data signal circuit of the HVAC control module to the IPM to enable the rear window defogger system. The IPM sends this message via class 2 to the RIM. The RIM energizes the RR DEFOG relay by grounding the control circuit of the RR DEFOG 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 send this message via the data signal circuit to the HVAC control module. The HVAC control module illuminates the rear window defogger indicator. Ground for the rear window defogger is provided by G404.
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.
The rear window defogger feature will not time out if the vehicle speed is above 48 km/h (30 mph).
If the battery voltage is very low, the rear window defogger feature is disabled.
Rear Window Defogger Operation (w/oCJ2)
Battery positive voltage is supplied through the RR DEFOG fuse, in the rear fuse block, 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 the rear window defogger switch is depressed. 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 G404.
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.
The rear window defogger feature will not time out if the vehicle speed is above 48 km/h (30 mph).
If the battery voltage is very low, the rear window defogger feature is disabled.
