Heated Mirrors Malfunction

Heated Mirrors Malfunction

Diagnostic Instructions

* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.

* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.

* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.

Diagnostic Fault Information






Circuit/System Description

The rear defogger relay supplies voltage to the outside rearview mirror heater elements based on the current state of the rear window defogger. The relay supplies B+ through the driver/passenger mirror heating element control circuit when a request is seen.

Reference Information

Schematic Reference

Outside Rearview Mirror Schematics Outside Rearview Mirror Schematics

Connector End View Reference

Component Connector End Views Outside Rearview Mirror - Driver

Description and Operation

Outside Mirror Description and Operation Outside Mirror

Electrical Information Reference

* Circuit Testing Circuit Testing

* Connector Repairs Connector Repairs

* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections

* Wiring Repairs Wiring Repairs

Scan Tool Reference

Control Module References Control Module References for scan tool information.

Circuit/System Verification

1. Engine running.

2. Verify the E18 Rear Defogger Grid turns ON and OFF when commanding the Rear Defogger On and Off with a scan tool.

• If the E18 Rear Defogger Grid does not turn ON or OFF
Refer to Rear Window Defogger Malfunction Rear Window Defogger Malfunction.

• If the E18 Rear Defogger Grid turns ON and OFF

3. Verify the mirror glass of the A9A Outside Rearview Mirror-Driver and the A9B Outside Rearview Mirror-Passenger become warm when commanding the Rear Defogger On with a scan tool.

• If the mirror glass of the A9A Outside Rearview Mirror-Driver and the A9B Outside Rearview Mirror-Passenger do not become warm
Refer to Circuit/System Testing.

• If the mirror glass of the A9A Outside Rearview Mirror-Driver and the A9B Outside Rearview Mirror-Passenger become warm

4. All OK.

Circuit/System Testing

1. Ignition OFF and all vehicle systems OFF, disconnect the harness connector at the appropriate A9 Outside Rearview Mirror. It may take up to 2 minutes for all vehicle systems to power down.

2. Test for less than 10 ohms between the ground circuit terminal 7 and ground.

• If 10 ohms or greater

1. Ignition OFF.

2. Test for less than 2 ohms in the ground circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, repair the open/high resistance in the ground connection.

• If less than 10 ohms

3. Ignition ON, connect a test lamp between the control circuit terminal 6 and the ground circuit terminal 7.

4. Verify the test lamp turns ON and OFF when commanding the Rear Defogger On and Off with a scan tool.

• If the test lamp is always OFF

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the X50A Fuse Block-Underhood.

2. Test for infinite resistance between the control circuit and ground.

• If less than infinite resistance, repair the short to ground on the circuit.

• If infinite resistance

3. Test for less than 2 ohms in the control circuit end to end.

• If 2 ohms or greater, repair the open/high resistance in the circuit.

• If less than 2 ohms, replace the A9 Outside Rearview Mirror.

• If the test lamp is always ON

1. Ignition OFF, remove the test lamp, disconnect the harness connector at the X50A Fuse Block-Underhood, ignition ON.

2. Test for less than 1 V between the control circuit and ground.

• If 1 V or greater, repair the short to voltage on the circuit.

• If less than 1 V, replace the X50A Fuse Block-Underhood

• If the test lamp turns ON and OFF

5. Test or replace the A9 Outside Rearview Mirror.

Repair Instructions

Perform the Diagnostic Repair Verification Verification Tests after completing the repair.

Outside Rearview Mirror Glass Replacement Outside Rearview Mirror Glass Replacement

Fuse Block Replacement Fuse Block Replacement