Volt

Automatic Day-Night Mirrors Malfunction

The inside rearview mirror uses 2 photocell sensors. One sensor is the rear light sensor, located on the face side of the mirror, facing the rear of the vehicle. The rear light sensor is used to determine light conditions present at the mirror face. The other sensor is the front light sensor, located on the backside of the mirror, facing the front of the vehicle. The front light sensor is used to determine the exterior light conditions at the front of the vehicle. With a low exterior light condition detected by the front light sensor and a high light condition from the rear light sensor, the inside rearview mirror will automatically darken the face of the inside rearview mirror.

With the gear selector lever in the REVERSE position, reverse lamp control voltage is supplied as an input to the inside rearview mirror. The mirror monitors this input to disable the automatic day-night feature. This allows the driver to see objects in the mirror clearly when backing up, regardless of the rear light sensor status.

Schematic Reference

Inside Rearview Mirror Schematics

Connector End View Reference

Component Connector End Views

Description and Operation

Automatic Day-Night Mirror Description and Operation

Electrical Information Reference

Scan Tool Reference

Control Module References for scan tool information

1. Vehicle in Service Mode, headlamps ON, vehicle in PARK, cover the front light sensor with a towel or other suitable item. Shine a torch at the rear light sensor while observing the inside rearview mirror face. The inside rearview mirror face should dim.
2. Vehicle ON, hand brake applied, place the transmission in REVERSE. The inside rearview mirror face should transition from dim to bright.

1. Vehicle OFF, disconnect the harness connector at the A10 inside rearview mirror.
2. Wait 1 minute, test for less than 10 Ω between the ground circuit terminal 5 and ground.

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

3. Vehicle in Service Mode, verify that a test lamp illuminates between the ignition circuit terminal 2 and ground.

⇒	If the test lamp does not illuminate test the ignition circuit for an open/high resistance or short to ground.

4. Vehicle ON, hand brake applied, vehicle in REVERSE, verify that a test lamp illuminates between the reverse lamp control circuit terminal 1 and ground.

⇒	If the test lamp does not illuminate test the control circuit for an open/high resistance or short to ground. If the circuit tests normal, refer to Reverse Lamps Malfunction .

5. If all circuits test normal, test or replace the A10 inside rearview mirror.

Perform the Diagnostic Repair Verification after completing the diagnostic procedure.

Inside Rearview Mirror Replacement