Chrysler 2006 Town and Country - Manual (Page 166)

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. If this occurs, the compass variance must be set.
NOTE: Magnetic materials should be kept away from
the overhead console.
166 UNDERSTANDING THE FEATURES OF YOUR VEHICLE