How to Adjust the Compass on an OnStar Mirror

Quick Calibration
1. Start the vehicle.
2. Locate the on/off button on the rearview mirror.
3. Press and hold the on/off button until Cal is displayed in the compass window.
4. Wait a few seconds for the compass window to display a north, south, east or west direction. If Cal remains instead of the compass displaying a direction you will need to calibrate the compass manually.
Manual Calibration
5. Start the vehicle.
6. Locate the on/off button on the rearview mirror.
7. Activate compass calibration mode by pressing and holding the on/off button until Cal is displayed in the compass window.
8. Drive the vehicle in 360 degree circles less than 5 miles per hour until the compass reads a direction.
Compass Variance
9. Use a magnetic variation zone map to determine your geographical location and the zone number which references your location.
10. Start the vehicle.
11. Locate the on/off button on the rearview mirror.
12. Make sure the compass displays a direction. If not you will need to calibrate the compass following the steps in Section 2.
13. Press and hold the on/off button on the rearview mirror until a zone number appears.
14. Press and release the on/off button causing the zone number to change. Continue to press and release the on/off button until the correct zone number is displayed.