Inside Rearview Mirror with the Automatic Day/Night Feature System Operation

WARNING: This page is about a different car, the 2002 Buick Regal and 2002 Buick Century. However, it is still accessible from the selected car via links, so may be relevant.

With the ignition switch in the ON position, ignition 3 voltage is supplied through the HVAC fuse to the inside rearview mirror. The inside rearview mirror uses 2 photocell sensors in order to determine light conditions in the front and the back of the vehicle. At night, with the automatic Day/Night feature enabled, the mirror automatically darkens to reduce the glare from the headlamps from behind. In the daytime, the mirror is in a normal state. With the gear selector lever in the REVERSE position, backup lamp supply voltage is supplied as an input to the inside rearview mirror. The inside rearview mirror will gradually change to a normal state as a result of the backup lamp supply voltage input. Ground for the inside rearview mirror is provided by G402.

The inside rearview mirror will also darken the driver outside rearview mirror (w/DR2). The inside rearview mirror supplies a low reference circuit and a signal circuit to the driver outside rearview mirror. Refer to OUTSIDE MIRROR DESCRIPTION AND OPERATION in Doors for further description and operation of the driver outside rearview mirror.