2008 Chevrolet HHR Owner's Manual - Page 118
2008 Chevrolet HHR Manual
Page 118 highlights
Compass Calibration If a compass direction, (N for North for example) does not appear, there may be a strong magnetic field interfering with the compass. This can be caused by a magnetic antenna mount, note pad holder, or similar objects. If the word CAL appears in the compass window, the compass may need to be reset or calibrated. To calibrate the compass, do the following: 1. Make sure CAL is displayed on the mirror. If not, press and hold the on/off button until CAL displays. 2. While CAL is displayed, drive the vehicle in circles at 5 mph (8 km/h) or less until a direction appears on the mirror. Compass Variance 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. The compass must be adjusted to compensate for compass variance if the vehicle is driven outside zone eight. To adjust for compass variance, do the following: 1. Find your current location and variance zone number on the following zone map. 2-40 2. Press and hold the compass button until a Z and a zone number appears on the mirror. 3. Once the zone number appears on the mirror, press the compass button quickly until the correct zone number displays. If CAL appears in the compass window, the compass may need calibration. See "Compass Calibration" listed previously.