2007 Buick Terraza Owner's Manual - Page 229

Compass Calibration Under certain circumstances, such as during a long distance cross-country trip, it will be necessary to compensate for compass variance and reset the zone through the DIC. Compass variance is the difference between the earth's magnetic north and true geographic north. If not adjusted to account for compass variance, the compass in the vehicle could give false readings. In order to do this, the compass must be set or calibrated to the variance zone in which the vehicle is traveling. To adjust for compass variance, use the following procedure: 1. Press the menu button until COMPASS ZONE displays. 2. Find the vehicle's current location and variance zone number on the map. 3. Press the set/reset button to scroll through and select the appropriate variance zone. 229