GM Service Manual Online
For 1990-2009 cars only

If you have the Memory Seat and Mirrors feature, the passenger's outside rearview mirror includes a tilt-down feature that operates when the shift lever is in REVERSE (R). This feature assists the driver, improving rear obstacle detection. When the vehicle is shifted out of REVERSE (R), the passenger mirror will return to its original position after a five-second delay. This delay prevents movement of the mirror if multiple gear transitions (REVERSE (R) to AUTOMATIC OVERDRIVE (Overdrive) to REVERSE (R)) occur during a parallel parking maneuver. This feature can be programmed on or off through the personal choice selection menu. See DIC Vehicle Personalization for programming instructions.