2007 GMC Sierra 1500 Pickup Owner's Manual - Page 188

Outside Convex Mirror Outside Heated Mirrors The vehicle may have outside heated mirrors which helps clear them of condensation, snow, and ice. The mirror heat is controlled by pressing the outside mirror button, if the vehicle has a sliding rear window, or the rear window defogger button. See "Rear Window Defogger" under Dual Automatic Climate Control System on page 235 for further information. The mirror heat will turn off about 10 minutes after the button is pressed. Press the button again if additional warming time is needed. {CAUTION: A convex mirror can make things (like other vehicles) look farther away than they really are. If you cut too sharply into the right lane, you could hit a vehicle on your right. Check your inside mirror or glance over your shoulder before changing lanes. Your passenger's side mirror is convex. A convex mirror's surface is curved so you can see more from the driver's seat. 188