Window Defogger Operation Test

Electrically Heated Rear Window Defogger operation can be easily checked in three steps:

1. Use ATC, Manual Heater-A/C self diagnostics, or the DRB III scan tool to check fault codes and control button operation. Note, this does not check the EBL system. There are no fault codes that can check for the EBL grid, relay, or wiring. Refer to steps 2 and 3 for system test.
2. Perform system test with voltmeter.

Rear Window Defogger Relay Test:

3. Check voltages at rear grid relay and refer to Rear Widow Defogger Relay Test table.