Window Defogger Operation Test

Electrically Heated Rear Window Defogger operation can be easily checked in three steps:
1. Use ATC or MTC self diagnostics, or the DRB III scan tool to check fault codes and control button operation. (Refer to HEATING & AIR CONDITIONING - DIAGNOSIS AND TESTING - SELF DIAGNOSTICS) 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 tests.
2. Perform a system test with a voltmeter. (Refer to HEATED GLASS - DIAGNOSIS AND TESTING - SYSTEM TEST)
3. Check the voltages at the rear grid relay. (Refer to REAR WINDOW DEFOGGER RELAY - DIAGNOSIS AND TESTING)