2005 Saturn Ion Owner's Manual - Page 101

Compass Variance Compass variance is the difference between earth's magnetic north and true geographic north. If not adjusted to account for compass variance, the mirror's compass could give false readings. The mirror is set in 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. To adjust for compass variance: 1. Find the current location and variance zone number on the following zone map. 2. Press and hold the on/off button for five seconds until the word ZONE appears in the display. The compass is now in zone mode. 3. Press and release the on/off button within five seconds until the new zone number appears in the display. The display will show a compass direction within a few seconds. 2-35