Rear Window Defogger Function Test

CAUTION: Be careful not to scratch or damage the defogger wires with the tester probe.

Function Test:

1. Check for voltage between the positive terminal and body ground with the ignition switch and the defogger switch ON. There should be battery voltage.
- If there is no voltage, check for:
- Faulty defogger relay.
- An open in the BLK/GRN wire.
- If there is battery voltage, go to step 2.
2. Disconnect the positive terminal, check for continuity between the negative terminal and body ground. If there is no continuity, check for an open in the defogger ground wire.
3. Reconnect the positive terminal, touch the voltmeter positive lead to the middle of each defogger wire, and the negative lead to the negative terminal. There should be approximately 6 V with the ignition switch and the defogger switch ON.
- If the voltage is as specified, the defogger wire is OK.
- If there is battery voltage, the defogger wire is broken on the negative side.
- If there is no voltage, the defogger wire is broken on the positive side.