Heated Glass Element: Testing and Inspection

Rear Window Defogger Function Test

NOTE:

- Before testing, check the No. 8 (20 A) fuse in the under-hood fuse/relay box and the No. 36 (10 A) fuse in the under-dash fuse/relay box.
- Aftermarket window tinting should be removed before testing.
- With the defogger ON, holding a cup of hot water to the rear window will form steam that can assist in diagnosing a broken or under-performing grid line or section.
- Be careful not to scratch or damage the defogger wires with the tester probe.

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/climate control unit.
- An open in the GRN 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 0.2V.

- If there is less than 0.2V, go to step 4.
- If there is more than 0.2V, check for :
- An open or high resistance in the wire.
- Poor ground (G602) or an open in the ground wire.

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