Diagnosis And Testing - Electric Back Light (EBL) System

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

Fig 1: Rear Window Glass Grid Test

Courtesy of CHRYSLER GROUP, LLC

1. Use a scan tool and check for Diagnostic Trouble Codes (DTCs) monitored by the Body Control Module (BCM). If any applicable DTCs are found, repair as required. The rear defog applicable DTCs are as follows; the rear defog function is not allowed to activate when any of the following DTCs are active (rear defog operation is allowed when these DTCs are stored).
   • B101E-19 - REAR WINDOW DEFROST RELAY DRIVER - OVER CURRENT
   • U0207-86 - ROOF CONTROL MODULE - SIGNAL INVALID
   • U0207-87 - ROOF CONTROL MODULE - NO SIGNAL
   • U0207-8F - ROOF CONTROL MODULE - SIGNAL ERRATIC
   • U1802-08 - LIN BUS - GENERAL SIGNAL FAILURE
2. If the vehicle is a Cabrio (soft top). Confirm the soft top roof is closed and there are no roof control module DTCs active (reported by the BCM). The rear defog will not activate when the roof is not closed, including when the soft top roof is not calibration. If applicable, fix/calibrate the soft top roof prior to continuing.
3. 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.
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 (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 being rear by the BCM (there is no DTC to indicate a failed switch or open switch connection). Using the scan tool find the rear defog monitor in the BCM module data. Press and release the rear defog switch while monitoring; if the BCM input monitor does not toggle (ON/OFF) repair the open connection between the switch and BCM or replace the failed switch.
   • 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 SYSTEM WIRING DIAGRAMS .
5. 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). Refer to STANDARD PROCEDURE  .
6. 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. Refer to REMOVAL .