The automatic day-night mirror has an autocal compass which automatically calibrates, during normal driving conditions, in order to prevent the vehicle's 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.

1. If the letter "C" should ever appear in the compass window, the mirror may need calibration. The mirror can be calibrated in one of two ways.
2. Drive the vehicle in complete circles (360   degrees) at 5  mph (8   km/h) or less until the display reads a direction, or
3. Drive the vehicle on your everyday routine.
4. The mirror is set at zone eight upon leaving the factory. If you live outside zone eight it will be necessary to adjust the compass to compensate for compass variance.
5. Press and hold the COMPASS button located at the bottom of the mirror until a zone number appears in the display.
6. Find your current location and variance zone number. Refer to Automatic Day/Night Mirror - United States Compass Zones or Automatic Day/Night Mirror - World Compass Zones .
7. Press the COMPASS button on the bottom of the mirror until the zone number appears in the display. After you stop pressing the button, the display will show a compass direction within a few seconds. This is the automatic calibration mode. Drive in a circle to calibrate the mirror. (See the first part of Calibrating the Automatic Day-Night Mirror Compass Manually).

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

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. Don't drive faster than 10 mph (16 km/h).
5. Drive in circles until the CALIBRATE light goes out. It usually takes one to five circles.
6. Your compass should be calibrated. You will know this when the direction bars are on and the CALIBRATE light is off.

Do not turn on the rear defog if you are trying to calibrate. The system will not allow the calibration. You will hear the chime, and CALIBRATE will flash for as few seconds.

Changing Zone Numbers on Automatic Day-Night Mirror Compass (Pontiac)

1. Press and hold the MODE button until the zone and zone number appear.
2. Release the MODE button.
3. Press the MODE button until your number appears.
4. In a few seconds, the zone number and ZONE turn off, and the new zone number is remembered by the compass.