2002 GMC Envoy Owner's Manual - Page 121

Automatic Dimming Feature When turned on, an electrochromic mirror automatically dims to the proper level to minimize glare from any headlamps behind you after dark. The automatic dimming feature is turned on and off by pressing the far left button, located on the lower part of the mirror face, for up to three seconds. A light on the mirror will be lit when the feature is turned on. It will go out when the feature is turned off. Compass Operation Press the on/off button once to turn the compass on or off. There is a compass display in the window in the upper right corner of the mirror face. The compass displays a maximum of two characters. For example, "NE" is displayed for north-east. Compass Calibration Press and hold the on/off button down for nine seconds to activate the compass calibration mode. "CAL" will be displayed in the compass window on the mirror. The mirror can be calibrated in one of two ways: D Drive the vehicle in circles at 5 mph (8 km/h) or less until the display shows "CAL," or D drive the vehicle on your everyday routine. Compass Variance (This method may take longer to calibrate). The mirror 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, such 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 your current location and variance zone number on the map. 2-52