2009 Dodge Grand Caravan Owner's Manual - Page 256

254 UNDERSTANDING YOUR INSTRUMENT PANEL Compass/Temperature Display Compass Variance Compass Variance is the difference between Magnetic North and Geographic North. To ensure compass accuracy, the compass variance should be properly set according to the variance map for the zone where the vehicle will be driven. When properly set, the compass will automatically account for this difference. NOTE: • A good calibration requires a level surface and an environment free from large metallic objects such as buildings, bridges, underground cables, railroad tracks, etc. • Magnetic and battery powered devices, (such as cell phones, iPod's, radar detectors, PDA's and laptops) should be kept away from the top of the instrument panel. This is where the compass module is located and such devices may interfere and cause false compass readings. U.S. Variance Zone Map