Heated Glass Element: Testing and Inspection

ELECTRIC BACKLIGHT (EBL) SYSTEM

NOTE:
- Illumination of the defogger switch indicator lamp means that there is electrical current available at the output of the rear window defogger logic circuitry, but does not confirm that the electrical current is reaching the rear glass heating grid lines.
- For circuit descriptions and diagrams of the EBL system, refer to WIRING DIAGRAM INFORMATION.

Operation of the electrical backlight (EBL) system can be confirmed by the following:
1. Turn the ignition switch to the On position. Set the rear window defogger switch in the On position. The rear window defogger operation can be checked by feeling the rear window glass. A distinct difference in temperature between the grid lines and the adjacent clear glass should be detected within three to four minutes of operation.

Grid Line Test:

2. If a temperature difference is not detected, use a 12-volt DC voltmeter and contact the rear glass heating grid terminal B with the negative lead, and terminal A with the positive lead. The voltmeter should read battery voltage. If the voltmeter does not read battery voltage, check the following:
- Confirm that the ignition switch is in the On position.
- Make sure that the rear glass heating grid feed wires and ground wires are connected to the window terminals. Confirm that the ground wires have continuity to ground.
- Check that fuse 7 (15 amp) in fuse block #1 and fuse 10 (30 amp) in the fuse/relay block are OK. The fuses must be tight in there receptacles and all electrical connections must be secure.
3. When the above steps have been completed and the rear glass heating grid is still inoperative, one or more of the following is faulty.
- Rear window defogger switch in the instrument panel.
- Rear window defogger (EBL) relays in the fuse/ relay block.
- Rear window defogger (EBL) relay control circuity in the rear window defogger module.
- 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 the power feed or ground wire not connected, for the entire heating grid to be inoperative).
4. If the system operation has been verified but the defogger switch indicator does not illuminate, check for voltage at the defogger indicator from the rear window defogger module when the defogger switch is activated. If power is present, replace the rear window defogger switch.
5. If broken defogger grid lines are suspected, use a 12-volt DC voltmeter and contact terminal B with the negative lead and each rear glass heating grid line at it's mid-point with the positive lead. The voltmeter should read approximately 6 volts at each grid line mid-point C. If the voltmeter does not read approximately 6 volts, repair the open grid line(s).