FREE REPAIR MANUALS & LABOR GUIDES 1982-2013 Vehicles
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Heated Glass Element: Testing and Inspection




Rear Window Defogger Function Test

NOTE:

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

- Before testing, check the No. 8 (30 A) [No. 8 (40 A)] fuse in the under-hood fuse/relay box and the No. 36 (10 A) fuse in the under-dash fuse/relay box.
[ ]: 2-door

1. Turn the ignition switch to ON (II), then turn the rear window defogger switch ON.

2. Measure the voltage between the positive terminal (A) and body ground.
There should be battery voltage.

- If there is no voltage, check for:
- Faulty rear window defogger relay.

- Faulty HVAC control unit/heater control panel.

- An open in the RED wire to the positive terminal.

- If there is voltage, go to step 3.

3. Measure the voltage between the negative terminal (B) and body ground. There should be less than 0.2 V.
If there is greater than 0.2 V, check for an open in the wire or poor ground (G801). If there is 0.2 V or less, go to step 4.

4. Touch the voltmeter positive probe to each point on each defogger wire, and the negative probe to the negative terminal.
- If the voltage is as specified, the defogger wire up to that point is OK.

- If the voltage is not as specified, repair the defogger wire.
- If it is more than specified at one of the points, there is a break in the negative half of the wire.

- If it is less than specified at one of the points, there is a break in the positive half of the wire.