The vehicle may have an automatic dimming inside rearview mirror with a compass and OnStar® controls. For more information about OnStar®, see OnStar® System .

The mirror has an eight-point compass display in the upper right corner of the mirror. When on, the compass automatically calibrates, or sets the driving direction, as the vehicle is driven. If the vehicle has the navigation option, the direction the vehicle is facing will be displayed on the navigation screen.

The automatic dimming feature comes on each time the vehicle is started.

To turn the automatic dimming feature on or off, press the on/off or AUTO button. The indicator light will illuminate when this feature is on.

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

When the ignition and the compass feature are on, the compass will show two character boxes for approximately two seconds. After two seconds, the mirror will display the current compass direction.

If after two seconds the display does not show a compass direction, (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, note pad holder, or similar object. If the letter C appears in the compass window, the compass may need to be reset or calibrated.

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

The compass can be calibrated by pressing and holding the on/off button until a C is shown in the compass display.

Compass variance is the difference between earth's magnetic north and true geographic north. If the mirror is not adjusted for compass variance, the 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 the vehicle is driven outside zone eight. Under certain circumstances, such as a long distance, cross-country trip, it will be necessary to adjust the compass variance.

To adjust for compass variance, do the following:

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



2. Press and hold the on/off button until a zone number appears on the display.
3. Once the zone number appears on the display, press the on/off button quickly until you reach the correct zone number. If C appears in the compass window, the compass may need calibration. See "Compass Calibration" listed previously.

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.