GM Service Manual Online
For 1990-2009 cars only

When you are sitting in a comfortable driving position, adjust the mirror so you can see clearly behind your vehicle. Hold the mirror in the center to move it up or down and side to side. The day/night adjustment allows you to adjust the mirror to avoid glare from the lamps behind you. Move the lever to the right for nighttime use and to the left for daytime use.

There may also be three OnStar® buttons located at the bottom of the mirror face. See your dealer/retailer for more information on the system and how to subscribe to OnStar®. See OnStar® System for more information on the services OnStar® provides.