GM Service Manual Online
For 1990-2009 cars only

Your vehicle may have an automatic-dimming rearview mirror with a compass.

(On/Off): This is the on/off button for the automatic dimming feature and compass.

Automatic Dimming Mirror Operation

The automatic dimming mirror function is turned on automatically each time the ignition is started. To operate the automatic dimming mirror, do the following:

The automatic dimming mirror comes on each time the ignition is turned to start. To turn the automatic dimming feature off or back on, press the on/off button. The indicator light on the mirror is lit when the automatic dimming feature is on.

Compass Operation

Press the on/off button once to turn the compass on or off.

There is a compass display in the window in the upper right corner of the mirror face. The compass displays a maximum of two characters. For example, "NE" is displayed for north-east.

Compass Calibration

Press and hold the on/off button to activate the compass calibration mode. CAL will be displayed in the compass window on the mirror.

The compass can be calibrated by driving the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction.

Compass Variance

Compass variance is the difference between earth's magnetic north and true geographic north. The mirror is set to zone eight upon leaving the factory. It will be necessary to adjust the compass to compensate for compass variance if you live outside zone eight. Under certain circumstances, such as during a long distance cross-country trip, it will be necessary to adjust for compass variance. If not adjusted to account for compass variance, your compass could give false readings.

To adjust for compass variance, do the following:

  1. Find your current location and variance zone number on the following zone map.

  2. Object Number: 806305  Size: B4
  3. Press and hold the on/off button for six seconds. Release the button when (FOR ZONE) is displayed. The number shown is the current zone number.
  4. Scroll through the zone numbers that appear in the window on the mirror by pressing the on/off button. Once you find your zone number, release the button. After about four seconds, the mirror will return to the compass display, and the new zone number will be set.