2005 Buick LeSabre Owner's Manual - Page 98

Compass Calibration When on, the compass automatically calibrates as the vehicle is driven. If, after two seconds, the display does not show a compass direction, (N for North, for example), there may be a strong magnetic field interfering with the compass. Such interference may be caused by a magnetic antenna mount, magnetic note pad holder, or a similar magnetic item. If the letter C should ever appear in the compass window, the compass may need calibration. The mirror can be calibrated by driving the vehicle in circles at 5 mph (8 km/h) or less until the display shows a direction. Mirrors equipped with OnStar® controls can be placed in calibration mode by pressing and holding the on/off button until a C is shown in the compass display. 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 the vehicle is 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, the compass could give false readings. To adjust for compass variance, do the following: 1. Find the current location and variance zone number on the following zone map. 2-34