GM Service Manual Online
For 1990-2009 cars only

The automatic day-night mirror consist of an automatic day-night rearview mirror with compass.

Power for the control of the automatic mirror comes from the IGN 1 fuse with the ignition in RUN, through CKT 39 (PNK) to the manual switch mounted in the mirror. The mirror switch has 3 positions:

    • OFF; system off
    • C; compass
    • C/M; compass and mirror input

The automatic rearview mirror uses 2 photocell sensors in order to determine light conditions in the front and the back of the vehicle. At night, as the glare of the headlamps from behind increases, the mirror gradually becomes darker in order to absorb the glare. In the daytime, the mirror is in a clear state.

When the gear selector is in reverse, the battery voltage, coming from the backup lamp switch through CKT 13 (LT GRN), is applied to the automatic rearview mirror. The mirror will gradually change to a clear state. Ground for the automatic day-night mirror is supplied by ground G203, through CKT 1850 (BLK).