Defogger System Operation Check

Rear Window Defogger Relay Test:

Electrically Heated Rear window defogger operation can be easily checked in three steps:
1. Use ATC or Heater-A/C self diagnostics or DRB lll scan tool to check fault codes to check 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.
Check voltages at rear grid relay and refer to Rear Widow Defogger Relay Test table.