Oldsmobile Bravada 2002 Owner's Manual page 114

Compass Variance
The mirror is set to 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, such as during a long
-
distance cross country trip, it will be necessary to
adjust for compass variance. Compass variance is
the difference between earth's magnetic north and
true geographic north. 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 map.
2-46
2. Press and hold the on/off button for six seconds.
Release the button when "ZONE" is displayed.
The number shown is the current zone number.
3. Scroll through the zone numbers that appear in
the compass/temperature window on the mirror by
pressing the on/off button. Once you find your zone
number, release the button. After about four seconds,
the mirror will return to the compass and temperature
display, and the new zone number will be set.