If the vehicle has this feature, an automatic dimming mirror automatically dims to the proper level to minimize glare at night from lights behind your vehicle. For more information about OnStar®, see OnStar® System .
The mirror includes a display in the upper right corner of the mirror that shows the compass reading.
(On/Off): Press this button to operate the automatic dimming and compass 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 comes on to indicate the automatic dimming is on.
Press and hold for about four seconds to manually turn the automatic dimming function on or off.
Compass Operation
Press once briefly to turn the compass on or off.
Compass Display
If the display reads CAL, the compass needs to be calibrated. For more information, see "Compass Calibration" later in this section.
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 is necessary to adjust the compass to compensate for compass variance if you live outside of zone eight. Under certain circumstances, as during a long distance cross-country trip, it is also necessary to adjust for compass variance.
To adjust for compass variance:
- Find your current location and variance zone number on the following zone map.
- Press approximately seven seconds until the word ZONE displays. The compass is now in zone mode.
- Press and release until the desired zone number displays. After approximately four seconds of inactivity, the new zone number locks in and the compass display returns.
- Calibrate the compass as described below.
Compass Calibration
The compass may need calibration if one of the following occurs:
| • | 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. 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 for approximately 12 seconds or until CAL displays.
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
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.
