Jeep 2008 Grand Cherokee SRT - Manual (Page 189)

Compass Variance
Compass Variance is the difference between magnetic
North and Geographic North. In some areas of the
country, the difference between magnetic and geographic
North is great enough to cause the compass to give false
readings. For the most accurate compass performance,
the compass variance must be set using the following
procedure:
NOTE: Magnetic materials should be kept away from
the top of the right rear quarter window. This is where
the compass sensor is located.
UNDERSTANDING YOUR INSTRUMENT PANEL 189
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