2003 Buick Park Avenue Owner's Manual - Page 109

Compass Variance Compass variance is the difference between earth's magnetic north and true geographic north. 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 you live outside zone eight. Under certain circumstances, as during a long distance cross-country trip, it will be necessary to adjust for compass variance. If not adjusted to account for compass variance, your compass could give false readings. To adjust for compass variance, do the following: 1. Find your current location and variance zone number on the following zone map. 2. Press and hold COMPASS (or the on/off button for mirrors equipped with OnStarB controls) until a zone number appears in the display. 3. Once a zone number appears in the display, press the COMPASS button (or the on/off button for mirrors equipped with OnStarB controls) quickly until the correct zone number appears in the display. Stop pressing the button and the mirror will return to normal operation. If C appears in the compass window, the compass may need calibration. See "Compass Calibration" explained previously. 2-40