2002 GMC Sonoma Owner's Manual - Page 129

Variance is the difference between magnetic north and geographic north. In some areas, the difference between the two can be great enough to cause false compass readings. If this happens, follow these instructions to set the variance for your particular location: 1. Find your location on the zone map. Record your zone number. 2. Press and hold both the ON/OFF and the US/MET buttons. The display will go off. 3. After five seconds, VAR CAL (Variance Calibration) will appear on the display. When it does, release both buttons. 4. Press US/MET until your zone number appears on the display. 5. Press ON/OFF to enter your zone number. Your variance is now set. 2-59