1995 GMC Yukon Owner's Manual - Page 125

Compass Operation When the ignition is on and the mirror switch is in the position, the C/M compass display will show two character boxes for approximately two seconds. If, after two seconds, display does not show a compass heading the ("N' for North, for example), there be strong magnetic field interfering may with the compass. Such interference may include magnetic antenna mounts, a magnetic note pad holder, or a similar magnetic item. If removing these items does not correct the condition, see GM dealer for assistance. your When cleaning the mirror, use a paper towel similar material dampened or with glass cleaner.Do not spray glass cleaner directly on the mirror as that may cause liquid cleaner to enter the mirror housing. Compass Variance Under certain circumstances, as during a long distance cross-country trip, it will be necessary to adjust the compass to compensate for compass variance. Compass variance is the difference between earth's magnetic If North and true geographic North. not adjusted to account for compass variance, your compass could give false readings. To adjust for compass variance: 1. Press and hold the CAL switch, located at the bottomthe mirror of housing, for five seconds until a zone number appears display. in the 2. Find your current location and variance zone number on the following zone map. 2-53