GM Service Manual Online
For 1990-2009 cars only

The mirror can be adjusted two ways. First, to adjust the height of the mirror, adjust the arm that connects the mirror to the windshield. Second, adjust the angle of the mirror, by moving the mirror to a position that allows you to see out of the back window.

To reduce glare from headlamps behind you, move the lever toward you to the night position. To return the mirror to the daytime position, move the lever away from you.