2002 GMC Sonoma Owner's Manual - Page 123

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. The mirror will also return to its clear daytime state when the vehicle is put into REVERSE (R). Press the AUTO button at the base of the mirror to turn on the automatic feature. The button has an indicator light to show it is on. Press the OFF button to turn the automatic feature off. Time Delay The automatic mirror has a time delay feature which prevents unnecessary switching from the night back to the day position. This delay prevents rapid changing of the mirror as you drive under lights and through traffic. Cleaning the Photocells Use a cotton swab and glass cleaner to clean the photocells when necessary. Outside Manual Adjust Mirror Adjust your outside mirrors so you can see a little of the side of your vehicle and the area beside and behind your vehicle from a comfortable driving position. You can fold them in before entering a car wash. Pull the mirrors in toward the vehicle. Push the mirrors back out when finished. 2-53