Sometimes simpler is better, and it doesn’t get much simpler than using a compass to make sure you are traveling in the right direction. For the several model years General Motors has included a digital compass in the rearview mirror in most of their vehicles. OnStar, a subsidiary of General Motors, offers services through a button which is also located on the rearview mirror. Adjusting the compass in a review mirror equipped with OnStar is a fairly simple procedure.
Start the vehicle.
Locate the on/off button on the rearview mirror.
Press and hold the on/off button until “Cal” is displayed in the compass window.
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.
Start the vehicle.
Locate the on/off button on the rearview mirror.
Activate compass calibration mode by pressing and holding the on/off button until “Cal” is displayed in the compass window.
Drive the vehicle in 360 degree circles less than 5 miles per hour until the compass reads a direction.
Use a magnetic variation zone map to determine your geographical location and the zone number which references your location.
Start the vehicle.
Locate the on/off button on the rearview mirror.
Make sure the compass displays a direction. If not you will need to calibrate the compass following the steps in Section 2.
Press and hold the on/off button on the rearview mirror until a zone number appears.
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.
