Diagnostic Routine G

Diagnostic Routine G

Diagnostic Overview

The Auto-Dimming Mirror Does Not Operate Correctly

Refer to Wiring Diagram Set 124 for schematic and connector information Electrical Diagrams.

Normal Operation and Fault Conditions

REFER to Rear View Mirrors - Interior .

Visual Inspection and Diagnostic Pre-checks

- Inspect BCM (Body Control Module) fuse 38 (10A).

- Inspect for obstructed forward or rearward sensors.

- Inspect the interior mirror.

Pinpoint Test

1. CHECK THE OPERATION OF THE REVERSING LAMPS

1. Ignition ON.

2. Move the selector lever through the entire range.

Do the reversing lamps illuminate only in REVERSE?








2. VERIFY THE FORWARD AND REARWARD FACING SENSORS ARE NOT BLOCKED

1. Verify the forward and rearward facing sensors are not blocked. Sources of blockage can include:

- stickers, window decals or tags.
- fold-down screens for TVs or DVD (Digital Video Disc) players.
- non- OEM (Original Equipment Manufacturer) window tinting.

Were either of the sensors blocked?








3. CHECK OPERATION OF THE INTERIOR AUTO-DIMMING MIRROR- DAYLIGHT CONDITIONS

1. Ignition ON.

2. Use a bright lamp to illuminate the forward facing sensor. The mirror should adjust to a high reflectance mode (mirror will be clear).





Does the mirror adjust to the high reflectance (clear) mode?








4. CHECK OPERATION OF THE INTERIOR AUTO-DIMMING MIRROR- NIGHTTIME CONDITIONS WITH GLARE

1. Ignition ON.

2. NOTE: Covering the sensor with a finger or hand is not adequate.
Simulate nighttime conditions with glare:

- Cover the forward sensor with black electrical tape or other dark material.
- Illuminate the rearward facing sensor. The mirror should darken to a lower reflectance mode.





Did the mirror darken to a lower reflectance (darker) mode?








5. CHECK OPERATION OF THE INTERIOR AUTO-DIMMING MIRROR- NIGHTTIME CONDITIONS WITHOUT GLARE

1. Ignition ON.

2. NOTE: Covering the sensor with a finger or hand is not adequate.
Simulate nighttime conditions without glare by covering the rearward facing sensor. The mirror should adjust to the high reflectance mode.





Did the mirror adjust to the high reflectance (clear) mode?








6. CHECK OPERATION OF THE INTERIOR AUTO-DIMMING MIRROR- NIGHTTIME CONDITIONS WITH THE VEHICLE IN REVERSE

1. Ignition ON.

2. NOTE: Covering the sensor with a finger or hand is not adequate.
Simulate nighttime conditions with glare:

- Cover the forward sensor with black electrical tape or other dark material.
- Illuminate the rearward facing sensor (mirror should darken at this time).





3. Select REVERSE.

Did the mirror adjust to a high reflectance (clear) mode?








7. CHECK FOR VOLTAGE TO THE INTERIOR AUTO-DIMMING MIRROR

1. Ignition OFF.

2. Disconnect: Interior Auto-Dimming Mirror.

3. Ignition ON.

4. Measure:





Is the voltage greater than 11 volts?








8. CHECK FOR GROUND TO THE INTERIOR AUTO-DIMMING MIRROR

1. Ignition OFF.

2. Measure:





Is the resistance less than 3 ohms?








9. CHECK FOR VOLTAGE TO THE INTERIOR AUTO-DIMMING MIRROR REVERSE CIRCUIT

1. Ignition ON.

2. Select REVERSE.

3. Measure:





Is the voltage greater than 11 volts?