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 feature of the driver outside rearview mirror is controlled by the inside rearview mirror. The inside rearview mirror supplies a signal and a low reference to the driver outside rearview mirror. The voltage on the signal circuit of the driver outside rearview mirror varies between 0.5-1.5 volts depending on light conditions present at the inside rearview mirror. At night, with the automatic day-night feature enabled, the driver outside rearview mirror will automatically darken with the inside rearview mirror to reduce the glare from the headlamps from behind. The voltage on the signal circuit of the driver outside rearview mirror will be near 1.5 volts. In daytime conditions, the mirrors are in the normal state. The voltage on the signal circuit of the driver outside rearview mirror may be less than or near 0.5 volts. For more detailed information concerning automatic day night mirror operation refer to Automatic Day-Night Mirror Description and Operation.

Diagnostic Aids

This diagnostic assumes that the vehicles backup lamps are operating within specifications. If the backup lamps are inoperative, diagnose the backup lamps system before continuing with this procedure.

Circuit/System Testing

1. Ignition OFF, disconnect the harness connector at the inside rearview mirror.
2. Ignition OFF, test for less than 1.0 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, test for battery voltage between the ignition 1 voltage circuit terminal 13 and ground.

• If less than the specified range, test the voltage circuit terminal 13 for a short to ground or an open/high resistance.

4. Transmission in REVERSE, test for battery voltage between the backup lamps supply voltage circuit terminal 9 and ground.

• If less than the specified range, test the voltage circuit terminal 9 for a short to ground or an open/high resistance.

5. If all circuits test normal, test or replace the inside rearview mirror.

Repair Instructions

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

Rearview Mirror Replacement (DD7, DD8) Rearview Mirror Replacement (UE1).