Compass Variance- Page 115

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The mirror can be calibrated in one of two ways:

D

Drive the vehicle in circles at 5 mph (8 km/h) or less
until the display reads a direction, or

D

drive the vehicle on your everyday routine.

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

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 you live outside zone eight.
Under certain circumstances, 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 following zone map.

2. Press and hold COMPASS (or the on/off button for

mirrors equipped with OnStar controls) until a zone
number appears in the display.

3. Once a zone number appears in the display, press

COMPASS (or the on/off button for mirrors
equipped with OnStar controls) quickly until 
the correct zone number appears in the display. 
Stop pressing the button and the mirror will return 
to normal operation. If C appears in the compass
window, the compass may need calibration. 
See “Compass Calibration” explained previously.