2010 GMC Sierra 1500 Crew Cab Owner's Manual - Page 201

Park Tilt Mirrors If the vehicle has the memory package, the passenger and/or driver mirror tilts to a preselected position when the vehicle is in R (Reverse). This feature lets the driver view the curb when parallel parking. The mirror(s) return to the original position when the vehicle is shifted out of R (Reverse), or the ignition is turned off or to OFF/LOCK. Turn this feature on or off through the Driver Information Center (DIC). See DIC Vehicle Customization (With DIC Buttons) on page 4‑76 for more information. The passenger side mirror is convex shaped. A convex mirror's surface is curved so more can be seen from the driver seat. Outside Heated Mirrors For vehicles with heated mirrors: < (Rear Window Defogger): Press to heat the mirrors. If the vehicle has a towing mirror, only the upper glass of the mirror is heated. The lower convex part of the towing mirror is not heated. Depending on the vehicle's features, see "Rear Window Defogger" under, Climate Control System (With Heater Only) on page 4‑19 or Climate Control System (With Air Conditioning) on page 4‑20 or Dual Automatic Climate Control System on page 4‑23 for more information. Outside Convex Mirror { WARNING: 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 the right. Check the inside mirror or glance over your shoulder before changing lanes. 3-63