2006 Cadillac DTS Owner's Manual - Page 116

Compass Variance The zone is set to zone eight upon leaving the factory. It will be necessary to adjust the compass to compensate for compass variance if you live outside zone eight. Under certain circumstances, as during a long distance cross-country trip, it will be necessary to adjust for compass variance. Compass variance is the difference between earth's magnetic north and true geographic north. If not adjusted to account for compass variance, your compass could give false readings. To adjust for compass variance do the following: 1. Find the current location and variance zone number on the following zone map. 2. Press and hold the on/off button until a zone number appears in the display. 3. Once the zone number appears in the display, press the on/off button quickly until the correct zone number appears in the display. Stop pressing the button and the mirror will return to normal operation. If C appears in the compass window, the compass may need calibration. See Compass Calibration listed previously. 2-38