GM Service Manual Online
For 1990-2009 cars only

If the vehicle has this feature, the automatic dimming mirror automatically dims to the proper level to minimize glare at night from lights behind your vehicle.

The mirror also has a dual display in the upper right corner of the mirror that shows the compass reading and the outside temperature.

On/Off: Press this button to operate the automatic dimming, compass and temperature features.

Automatic Dimming Mirror Operation

The automatic dimming mirror function is turned on each time the ignition is started. A light near the on/off button will come on to indicate the automatic dimming is on.

If the automatic dimming function is off, press and hold the on/off button for four seconds to manually turn the system back on.

Temperature and Compass Display

Press the on/off button, located in the center, to cycle between °F, °C and off. If the display reads CAL, the compass needs to be calibrated. For more information, see "Compass Calibration" later in this section.

If an abnormal temperature reading is displayed for an extended period of time, please consult your dealer. Under certain circumstances, a delay in updating the temperature is normal.

Compass Variance

Compass variance is the difference between earth's magnetic north and true geographic north. If not adjusted to account for compass variance, the mirror's compass could give false readings. The mirror is set in 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, as during a long distance cross-country trip, it will be necessary to adjust for compass variance.

To adjust for compass variance:

  1. Find the current location and variance zone number on the following zone map.
  2. Press and hold the on/off button for five seconds until the word ZONE appears in the display. The compass is now in zone mode.
  3. Press and release the on/off button within five seconds until the new zone number appears in the display. The display will show a compass direction within a few seconds.

Object Number: 806305  Size: B4

Compass Calibration

The compass may need calibration if one of the following occurs:

    • If CAL is displayed while driving in the vehicle.
    • After approximately five seconds, the display does not show a compass heading (N for North, for example), there may be a strong magnetic field interfering with the compass. Such interference may be caused by a magnetic antenna mount, magnetic note pad holder, or a similar magnetic item.
    • The compass does not display the correct heading and the compass zone variance is set correctly.

In order to calibrate, CAL must be displayed in the mirror compass windows. If CAL is not displayed, push in the on/off button for approximately eight seconds or until CAL is displayed.

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.

Cleaning the Mirror

When cleaning the mirror, use a paper towel or similar material dampened with glass cleaner. Do not spray glass cleaner directly on the mirror as that may cause the liquid cleaner to enter the mirror housing.