GMC 2009 Savana - Manual (Page 165)

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 P (Park).
Press the vehicle information button until
PRESS
V 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.
Compass Calibration
The compass can be manually calibrated. Only calibrate
the compass in a magnetically clean and safe location,
such as an open parking lot, where driving the vehicle in
circles is not a danger. It is suggested to calibrate
away from tall buildings, utility wires, manhole covers, or
other industrial structures, if possible.
If CAL should ever appear in the DIC display, the
compass should be calibrated.
If the DIC display does not show a heading, for example,
N for North, or the heading does not change after
making turns, there may be a strong magnetic field
interfering with the compass. Such interference may be
caused by a magnetic CB or cell phone antenna
mount, a magnetic emergency light, magnetic note pad
holder, or any other magnetic item. Turn off the
vehicle, move the magnetic item, then turn on the
vehicle and calibrate the compass.
3-47