• | Perform the Diagnostic System Check - Vehicle prior to using this diagnostic procedure. |
• | Review Strategy Based Diagnosis for an overview of the diagnostic approach. |
• | Diagnostic Procedure Instructions provides an overview of each diagnostic category. |
Circuit | Short to Ground | Open/High Resistance | Short to Voltage | Signal Performance |
---|---|---|---|---|
Rearview Mirror Accessory Voltage Circuit | 1 | 1 | -- | -- |
Rearview Mirror Ground Circuit | -- | 1 | 1 | -- |
Backup Lamp Supply Voltage Circuit | 1 | 1 | 1 | -- |
1. Automatic Day/Night Rearview Mirror Inoperative |
The automatic day-night rearview mirror uses 2 photocell sensors that detects 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.
The automatic day-night feature of the inside rearview mirror may not operate properly or become inoperative due to a short to battery positive voltage in the backup lighting system.
Inside Rearview Mirror Schematics
Ignition ON, place the gear shifter into the drive position, cover the ambient light sensor that faces the front windshield. Shine a flashlight into the rearview mirror face. The face of the mirror should darken.
⇒ | If greater than 1.0 ohm, test the ground circuit for an open/high resistance. |
⇒ | If the test lamp does not illuminate, repair the voltage supply circuit for a short to ground or an open/high resistance. |
⇒ | If the voltage is greater than 0.6 volts, test the backup lamp supply voltage circuit for a short to voltage. |
⇒ | If the voltage is not 12 volts, test the backup lamp supply voltage circuit for an open/high resistance. |
Perform the Diagnostic Repair Verification after completing the diagnostic procedure.
• | Control Module References for BCM replacement, setup, and programming |