Rear Window Defogger Switch Function Test

REAR WINDOW DEFOGGER SWITCH / FUNCTION TEST

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







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.
- faulty defogger switch.
- faulty integrated control unit.
- an open in the BLK/GRN wire.

* If there is battery voltage, go to step 2.

2. Turn the rear window defogger switch OFF. Check for continuity between the negative terminal and body ground.
* If there is no continuity, check for an open in the defogger ground wire.
* If there is continuity, go to step 3.

3. Touch the voltmeter positive lead to the halfway point of each defogger wire, and the negative lead to the negative terminal.
There should be approximately 6 V with the ignition switch and defogger switch ON.
* If the voltage is as specified, the defogger wire is OK.
* If the voltage is not as specified, repair the defogger wire:
- If it is more than 6 V, look for the damage on the negative half on the grid.
- If it is less than 6 V, look for the damage on the positive half of the grid.