Chevrolet 2008 Equinox Owner's Manual page 175

Under certain circumstances, such as during a long
distance cross-country trip or moving to a new state
or province, it will be necessary to compensate for
compass variance by resetting the zone through
the DIC if the zone is not set correctly.
Compass variance is the difference between the
earth's magnetic north and true geographic north.
If the compass is not set to the zone where you live,
the compass may give false readings. The compass
must be set to the variance zone in which the vehicle
is traveling.
To adjust for compass variance, use the following
procedure:
Compass Variance (Zone) Procedure
1. Do not set the compass zone when the vehicle
is moving. Only set it when the vehicle is in
PARK (P).
Press the vehicle information button until
V
PRESS TO CHANGE COMPASS ZONE
displays.
2. Find the vehicle's current location and variance
zone number on the map.
Zones 1 through 15 are available.
3. Press the set/reset button to scroll through and
select the appropriate variance zone.
4. Press the trip/fuel button until the vehicle heading,
for example, N for North, is displayed in the DIC.
5. If calibration is necessary, calibrate the compass.
See "Compass Calibration Procedure" following.
3-47