GM Service Manual Online
For 1990-2009 cars only

If the vehicle has memory mirrors, the outside mirrors have park tilt mirrors . This feature tilts the driver's side and passenger side mirror to a factory programmed position when the vehicle is in R (Reverse). This feature may be useful in allowing you to view the curb when you are parallel parking.

When the vehicle is shifted out of R (Reverse) and either a five second delay has occurred, or the ignition is turned to LOCK/OFF, the driver and passenger side mirrors return to their original position.

See DIC Vehicle Customization for more information.