Electric Backlight System

DIAGNOSIS AND TESTING - ELECTRIC BACKLIGHT (EBL) SYSTEM

NOTE: Illumination of the defogger switch indicator lamp does not necessarily mean that electrical current is reaching the rear glass heating grid lines.

NOTE: See Wiring Information for circuit descriptions and diagrams of the rear window defogger system.

Operation of the rear window defogger (Electric Back Light (EBL)) system can be confirmed by the following:





1. Use a scan tool and check for Diagnostic Trouble Codes (DTCs) related to the U-Connect Touch (TM) screen module, Telematics Gateway (TGW) or the A/C heater module. If no DTCs are found, go to 2. If any DTCs are found, repair as required, then proceed to 2.
2. With the ignition in the Run position, press a rear window defogger switch to on.
3. Rear window defogger operation can be checked by feeling the rear window glass (5), or the heated outside rear view mirror glass, when equipped with heated mirrors. After three to four minutes of operation, a distinct difference in temperature should be detected between the clear glass area and the heated glass area, or the heated mirror glass.
4. If a temperature difference is not detected, use a 12 volt Direct Current (DC) voltmeter and contact the rear glass heating grid terminal A (8) with the negative lead, and terminal B (4) 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 the Run position.
- Confirm the rear window defogger switch is on.
- Check the EBL fuse in the Power Distribution Center (PDC). The fuse must be tight in its receptacle and its electrical connections must be secure.
- 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 PDC.
- Confirm the EBL ground wire (1) is connected to the heating grid negative terminal and that there is continuity to ground.

5. Visually inspect the bus bars, horizontal defogger grid lines (6) and vertical defogger grid lines (7) for damage which could cause an open circuit condition. If a broken grid line or bus bar is found, repair as required Service and Repair.
6. If the EBL system operation has been verified but the rear window defogger indicator lamp in the switchbank does not illuminate, replace the entire switchbank pod Instrument Cluster Switch Pod - Removal.