Compass Variance - Chevrolet 2007 TrailBlazer Owner's Manua

Compass Variance

Compass variance is the difference between earth's
magnetic north and true geographic north. 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.
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 the on/off button for
six seconds. Release the button when
(FOR ZONE) is displayed. The number shown
is the current zone number.
3. Scroll through the zone numbers that appear in
the 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 display,
and the new zone number will be set.
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