GM Service Manual Online
For 1990-2009 cars only

Calibrating the Automatic Day-Night Mirror Compass using the Autocal Feature

The automatic day-night mirror has an autocal compass which automatically calibrates, during normal driving conditions, in order to prevent vehicles unique magnetic fields from causing the mirror to display the wrong compass direction. During calibration, the letter "C" displays. Calibration is completed when the "C" changes to the correct directional heading. Once calibrated, the mirror does not need to be recalibrated. When you turn the ignition switch to the OFF position, calibration does not change.

Calibrating the Automatic Day-Night Mirror Compass Manually (Buick, Oldsmobile)

  1. If the letter "C" appears in the compass window the mirror will need calibration.
  2. Drive the vehicle in circles at 8 km/h (5 mph) or less until the display reads a direction.
  3. Drive the vehicle on your everyday routine.

Calibrating the Automatic Day-Night Mirror Compass Manually (Pontiac)

If the CALIBRATE light comes on, calibrate the compass as follows:

    Important: Do not turn on the rear defogger when calibrating. Listen for a chime and the CALIBRATE light flashing for a few seconds indicating he system will not allow the calibration.

  1. Drive the car to an open, flat area.
  2. Press and hold the mode button until the CALIBRATE light reappears.
  3. Release the MODE button. The heading display will start to rotate.
  4. Drive the car in small circles. Do not drive faster than 16 km/h (10 mph.
  5. Drive in circles until the CALIBRATE light goes out approximately 1-5 minutes.
  6. The compass will be calibrated when the direction bars are ON and the CALIBRATE light is OFF.