1999 Buick Riviera Owner's Manual - Page 108

yellowblue Mirrors Inside Day/Night Rearview Mirror Electrochromic Day/Night Rearview Mirror (Option) Your vehicle may have an automatic electrochromic day/night rearview mirror. When this feature is turned on, the mirror automatically changes to reduce glare from headlamps behind you. A photocell on the mirror senses when it is becoming dark outside. Another photocell built into the mirror face senses when headlamps are behind you. At night, when the glare is too high, the mirror will gradually darken to reduce glare (this change may take a few seconds). The mirror will return to its clear daytime state when the glare is reduced. When you are sitting in a comfortable driving position, adjust the mirror so you can see clearly behind your vehicle. Grip 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 lights behind you. Pull the tab toward you for night use; push it away from you for daytime use. 2-46