Heated Glass Element: Testing and Inspection

REAR WINDOW DEFOGGER SYSTEM
The electrically heated rear window defogger operation can be checked in vehicle in the following manner:

1. Turn ignition switch to the On position.

NOTE: Illumination of the rear window defogger LED indicator means that there is power available at the switch, but does not necessarily verify system operation.

2. The rear window defogger operation can be checked by feeling the glass. Turn the rear defogger control switch to the On position. The rear window defogger LED indicator should illuminate and distinct difference in temperature between the grid lines and adjacent clear glass should be detected in three to four minutes of operation.

Rear Window Defogger:

3. If no difference in temperature between the grid lines and adjacent clear glass is detected in three to four minutes of operation, use a DC voltmeter and contact the negative lead to Point B, and the positive lead to Point A. The voltmeter should read 10-14 volts.
4. If the voltmeter does not read 10-14 volts, the problem should be isolated in the following manner:
- Confirm that the ignition switch is On.
- Make sure that the heated rear window feed wire is connected to the terminal and that the ground wire is in fact grounded.
- Make sure that fuses 30 and 39 (10 amp) in the junction block are OK.

5. When the above steps have been completed and the system is still inoperative, one or more of the following could be defective. It may be necessary to connect a DRBIII(R) scan tool to perform further diagnostics. Refer to Body Diagnostic Procedures.
- Rear window defogger relay battery power circuit in the junction block.
- Rear window defogger relay in the junction block.
- Rear window defogger switch in the A/C-heater control.
- Rear window defogger relay control circuity in the body control module (BCM).
- Check for a loose wire connector or a wire pushed out of a connector.
- Rear window grid lines (all grid lines would have to be broken, or one of the feed wires not connected for the system to be inoperative).

6. If the system operation has been verified but LED indicator does not illuminate, replace the A/Cheater control.
7. For detailed wiring information, refer to Wiring Diagrams.