GM Service Manual Online
For 1990-2009 cars only

If your vehicle has this feature, the driver's outside mirror will adjust for the glare of headlamps behind you. This feature is controlled by the on and off settings found on the electrochromic inside mirror. See Automatic Dimming Rearview Mirror with OnStar®, Compass and Temperature Display or Automatic Dimming Rearview Mirror with Compass and Temperature Display for more information.