Heated Mirrors Inoperative

Heated Mirrors Inoperative

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. Initial Inspection and Diagnostic Overview
* Review Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Circuit/System Description

When you depress the rear defogger button, voltage is supplied to the REAR DEFOG relay coil and the heating elements in the outside rearview mirrors. Ground for the outside rearview mirrors are provided by G347.

When you start the engine and press the rear defogger switch for the first time, the defogger cycle lasts for 15 minutes. Further operation results in 7.5 minute defogger cycles. The defogger cycle resets to 15 minutes when you cycle the ignition to the OFF position and then to the ON position.

Circuit/System Verification

Ignition ON, command the rear window defogger ON and OFF with a scan tool. Observe the rear window defogger and heated outside mirror operation as the rear window defogger turns ON and OFF.

If the rear window defogger is inoperative, refer to Rear Window Defogger Malfunction. Testing and Inspection

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the appropriate outside rearview mirror.
2. Ignition OFF, test for less than 1 ohm of resistance between the ground circuit terminal A and ground.

• If greater than the specified value, test the ground circuit for an open/high resistance.

3. Ignition ON, connect a test lamp between the control circuit terminal C and ground.
4. Command the rear window defogger ON and OFF by pressing and depressing the rear window defog switch, the test lamp should turn ON and OFF when changing between the commanded states.

• If the test lamp is always ON, test the control circuit for a short to voltage.
• If the test lamp is always OFF, test the control circuit for a short to ground or an open/high resistance.

5. If all circuits test normal, replace appropriate outside rear view mirror.

Repair Instructions

Perform the Diagnostic Repair Verification after completing the diagnostic procedure. Verification Tests

Power Mirror Replacement