Automatic Day-Night Mirrors Inoperative

Automatic Day-Night 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

The automatic day-night rear view mirror uses 2 photocell sensors that detect an increase in light. One sensor is located in the rear side of the mirror. This sensor determines the light condition present at the mirror face. The other sensor is the ambient light sensor, located on the front of the mirror or windshield side. This sensor determines the amount of light present at the mirror. When the ambient light sensor senses a low light condition and a high light condition from behind at the headlight sensor, the inside rearview mirror will automatically darken the face of the mirror.

Circuit/System Verification

Ignition ON, observe the operation of each outside rearview mirror while using the outside rearview mirror switch. The appropriate mirror should move in the direction commanded.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the rearview mirror.
2. Test for less than 1 ohm of resistance between the ground circuit terminal 8 and ground.

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

3. Ignition ON, verify that a test lamp illuminates between the voltage supply circuit terminal 13 and ground.

• If the test lamp does not illuminate, test the voltage supply circuit for a short to ground or an open/high resistance.

4. With the transmission in PARK, test for less than 0.5 volts between the backup lamp supply voltage circuit terminal 9 and ground.

• If the voltage is greater than the specified range, test the voltage circuit for a short to B+.

5. With the transmission in REVERSE, test for greater than 11 volts between the backup lamp supply voltage circuit and ground.

• If less than the specified range, test the voltage circuit for an open/high resistance.

6. If all circuits test normal, replace the rearview mirror.

Repair Instructions

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

Inside Rearview Mirror Replacement