Heated Glass Element: Testing and Inspection

Rear Window Defogger Function Test

Upper Rear Window Defogger

NOTE:

- Before testing, check the No. A5 (40 A) fuse in the under-hood fuse/relay box and the No. B16 (7.5 A) fuse in the driver's under-dash fuse/relay box.
- Before testing, troubleshoot using B-CAN System Diagnosis Test Mode A.
- 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 upper rear window defogger A (1P) positive terminal (A) and body ground. There should be battery voltage.

- If there is no voltage, check for:
- Faulty rear window defogger relay.
- Faulty climate control unit.
- Faulty driver's climate control switch('10 model with navigation).
- Faulty passenger's climate control switch('11-12 models with navigation).
- An open or high resistance in the GRN wire to the positive terminal.

- If there is voltage, go to step 3.





3. Measure the voltage between upper rear window defogger B (1P) 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 ground (BLK) wire or poor ground (G601). If there is 0.2 V or less, go to step 5.

4. To avoid damaging the defogger grid, wrap a single strand of bare copper wire or aluminum foil around the voltmeter probe. Use the foil or wire as a contact brush when moving across the defogger grid.





5. Touch the voltmeter positive probe along 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 voltage is more than specified at one of the points, there is a break or high resistance toward the negative half of the wire.
- If voltage is less than specified at one of the points, there is a break or high resistance toward the positive half of the wire.

Lower Rear Window Defogger

NOTE:

- Before testing, check the No. A5 (40 A) fuse in the under-hood fuse/relay box and the No. B16 (7.5 A) fuse in the driver's under-dash fuse/relay box.
- Before testing, troubleshoot using B-CAN System Diagnosis Test Mode A Troubleshooting - B-CAN System Diagnosis Test Mode A.
- 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 lower rear window defogger A (1P) positive terminal (A) and body ground. There should be battery voltage.

- If there is no voltage, check for:
- Faulty rear window defogger relay.
- Faulty climate control unit.
- Faulty driver's climate control switch('10 model with navigation).
- Faulty passenger's climate control switch('11-12 models with navigation).
- An open or high resistance in the GRN wire to the positive terminal.

- If there is voltage, go to step 3.





3. Measure the voltage between lower rear window defogger B (1P) 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 ground (BLK) wire or poor ground (G601). If there is 0.2 V or less, go to step 5.

4. To avoid damaging the defogger grid, wrap a single strand of bare copper wire or aluminum foil around the voltmeter probe. Use the foil or wire as a contact brush when moving across the defogger grid.





5. Touch the voltmeter positive probe along 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 voltage is more than specified at one of the points, there is a break or high resistance toward the negative half of the wire.
- If voltage is less than specified at one of the points, there is a break or high resistance toward the positive half of the wire.