Compass Calibration; Compass Variance - Buick 2005 LeSabre Owner's Manual

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
in calibration mode by pressing and holding the
on/off button until a C is shown in the compass display.
2-34
®
controls can be placed

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.