Automatic Day - Night Mirrors

AUTOMATIC DAY-NIGHT MIRROR DESCRIPTION AND OPERATION

INSIDE REARVIEW MIRROR WITH THE AUTOMATIC DAY-NIGHT FEATURE SYSTEM COMPONENTS
The automatic day-night feature system consist of an inside rearview mirror.

POWER AND GROUND OF THE INSIDE REARVIEW MIRROR
- With the ignition ON, ignition voltage is supplied to the mirror from the IGN 1 fuse in the right rear fuse block.
- Ground for the mirror is provided by G402.

INSIDE REARVIEW MIRROR WITH THE AUTOMATIC DAY-NIGHT FEATURE SYSTEM OPERATION
The inside rearview mirror uses 2 photocell sensors. One sensor is the headlight sensor, located on the rear side of the mirror. The headlight sensor is used to determine light conditions present at the mirror face. The other sensor is the ambient light sensor, located on the front of the mirror or windshield side. The ambient light sensor is used to determine light conditions present at the mirror. With automatic day-night feature enabled, the mirror uses ambient light sensor to determine the exterior light condition. With a low light condition detected, and a high light condition from behind at the headlight sensor, the inside rearview mirror will automatically darken the face of the mirror.

In the daytime, the mirror is in a normal state because of the high light condition that is indicated by the ambient light sensor. With the gear selector lever in the REVERSE position, backup lamp supply voltage is supplied as an input to the inside rearview mirror. In night time conditions only, the mirror monitors this input to disable the automatic day-night feature which allows the face to gradually change to a normal state. This allows the driver to see objects in the mirror clearly when backing up.

COMPASS
The mirror uses two magnetic field sensors for compass direction. One sensor is for north and south, the other is for east and west. The mirror supplies a signal and low reference to each sensor. As the vehicle travels with or against the earth's magnetic pull, there will be a change in voltage on one or both sensors. As a result of the change in voltage, the mirror changes the heading on the compass display.

SWITCHES OF THE INSIDE REARVIEW MIRROR WITH THE AUTOMATIC DAY-NIGHT FEATURE
The inside rearview mirror has 2 switches that perform the following functions:
- The AUTO switch is used to enable the automatic day-night feature of the mirror. With the ignition in the ON position, depress the AUTO switch to enable the automatic day-night feature of the mirror. A green indicator will illuminate on the mirror when the automatic day-night feature is enabled.
- The OFF switch is used to disable the automatic day-night feature of the mirror.

SWITCHES OF THE INSIDE REARVIEW MIRROR WITH THE AUTOMATIC DAY-NIGHT FEATURE WITHOUT COMPASS WITH ONSTAR(R)
The inside rearview mirror has 4 switches that perform the following functions:
- The on/off switch for automatic day-night feature of the inside rearview mirror is located at the left side of the mirror. The on/off switch is used to enable or disable the automatic day-night feature of the mirror. With the ignition in the ON position, depress the on/off switch to enable the automatic day-night feature of the mirror. A green indicator will illuminate on the mirror when the automatic day-night feature is enabled. To disable the automatic day-night feature of the mirror, depress the on/off switch.
- The three switches on the right side of the mirror are for OnStar(R) operation. For more information, refer to OnStar Description and Operation in Cellular Communication.

SWITCHES OF THE INSIDE REARVIEW MIRROR WITH THE AUTOMATIC DAY-NIGHT FEATURE WITH COMPASS AND ONSTAR(R)
The inside rearview mirror has 4 switches that perform the following functions:
- The on/off switch located at the left side of the mirror performs the following functions:
- To enable or disable the automatic day-night feature of the mirror. With the ignition in the ON position, depress and hold the on/off switch for 4 seconds to enable the automatic day-night feature of the mirror. A green indicator will illuminate on the mirror when the automatic day-night feature is enabled.
To disable the automatic day-night feature of the mirror, depress and hold the on/off switch for 4 seconds.
- To turn the compass on and off. With the ignition in the ON position, depress the on/off switch to turn the compass on. Depress the on/off switch again to turn the compass off. The on/off switch is also used to place the compass into a calibration or zone mode. For more information, refer to Compass Calibration and Variance Procedure.
- The 3 switches on the right side of the mirror are for OnStar(R) operation. For more information, refer to OnStar Description and Operation in Cellular Communication.