2004 GMC Envoy Owner's Manual - Page 102

Mirrors Automatic Dimming Rearview Mirror with OnStar® and Compass Your vehicle may have an automatic-dimming rearview mirror with a compass and the OnStar® system. There are three additional buttons for the OnStar® system. See your dealer for more information on the system and how to subscribe to OnStar®. See OnStar® System on page 2-40 for more information about the services OnStar® provides. 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 compass can be calibrated by driving the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction. Mirror Operation When turned on, this mirror automatically dims to the proper level to minimize glare from any headlamps behind you after dark. O(On/Off): This is the on/off button for the automatic dimming feature and compass. Press the far left button, located below the the mirror face, for up to three seconds to turn the feature on and off. A light on the mirror will be lit while the feature is turned on. 2-36