Schematic Reference: Defogger Schematics

Did you perform the Stationary Windows Diagnostic System Check?

Go to Step 2

Go to Diagnostic System Check - Stationary Windows

1. Start the engine.
2. Observe the rear window defogger indicator on the HVAC Control Module.
3. Command the rear window defogger indicator ON and OFF, by depressing the rear window defogger switch on the HVAC Control Module.

Does the indicator remain illuminated?

Go to Step 3

Go to Testing for Intermittent Conditions and Poor Connections in Wiring Systems

1. Turn OFF the ignition.
2. Disconnect the Heated Outside Rearview Mirror and Rear Window Defogger relay.
3. Turn ON the ignition, with the engine OFF.
4. Observe the rear window defogger indicator on the HVAC Control Module.

Does the indicator remain illuminated?

Go to Step 4

Go to Step 5

Test the supply voltage circuit of the heated mirrors for a short to battery positive voltage. Refer to Circuit Testing and Wiring Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 6

Inspect for a poor connection at the Heated Outside Rearview Mirror and Rear Window Defogger relay. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 7

Inspect for a poor connection at the harness connector of the HVAC Control Module. Refer to Testing for Intermittent Conditions and Poor Connections and Connector Repairs in Wiring Systems.

Did you find and correct the condition?

Go to Step 9

Go to Step 8

Replace the Heated Outside Rearview Mirror and Rear Window Defogger relay.

Did you complete the replacement?

Go to Step 9

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Replace HVAC Control Module. Refer to HVAC Control Module Replacement in HVAC Systems - Automatic.

Did you complete the replacement?

Go to Step 9

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Operate the system in order to verify the repair.

Did you correct the condition?

System OK

Go to Step 3