Electric Backlight System

DIAGNOSIS AND TESTING - ELECTRIC BACK LIGHT (EBL) SYSTEM

NOTE: Illumination of the rear window defogger indicator lamp in the instrument cluster does not necessarily mean that electrical current is reaching the rear window glass heating grid.

NOTE: See Wiring Information for circuit descriptions and diagrams.

Operation of the EBL system can be confirmed by the following:






NOTE: Typical heated rear window glass shown.

1. Use a scan tool and check for Diagnostic Trouble Codes (DTCs) related to the Body Control Module (BCM) and the lower accessory switchbank. If no DTCs are found, go to 2. If any DTCs are found, repair as required.
2. Turn the ignition to RUN and press the rear window defogger switch to on. Rear window defogger operation can be checked by feeling the surfaces of the rear window glass. A distinct difference in temperature between the grid lines (5) and the adjacent clear glass should be detected within three to four minutes of operation.
3. If a temperature difference is not detected, use a 12 volt Direct Current (DC) voltmeter and contact the rear glass heating grid terminal A (1) with the negative lead, and terminal B (2) with the positive lead. The voltmeter should read battery voltage. If the voltmeter does not read battery voltage, check the following:
- Confirm the ignition is in RUN.
- Confirm the rear window defogger switch is on.
- Confirm the EBL feed wire (3) is connected to the heating grid positive terminal and that there is continuity between the heating grid and the EBL relay in the Power Distribution Center (PDC).
- Confirm the EBL ground wire (6) is connected to the heating grid negative terminal and that there is continuity to ground.
- Confirm the EBL relay in the PDC is operational. See Wiring Information.

4. If broken defogger grid lines or bus bars are suspected, use a 12 volt DC voltmeter and contact terminal A with the negative lead and each rear glass heating grid line at its mid-point C (4) with the positive lead. The voltmeter should read approximately 6 volts at each grid line mid-point. If the voltmeter does not read approximately 6 volts, repair the open grid line(s) or bus bar(s) Service and Repair.
5. If the EBL system operation has been verified but the rear window defogger indicator in the instrument cluster does not illuminate, replace the instrument cluster Instrument Cluster - Removal.