2008 GMC Yukon Owner's Manual - Page 148

Temperature and Compass Display Press the on/off button, located to the far left, briefly to turn the compass/temperature display on or off. If the display reads CAL, the compass needs to be calibrated. For more information, see "Compass Calibration" following. To adjust between Fahrenheit and Celsius: 1. Press and hold the on/off button for approximately four seconds until either a flashing F or C appears. 2. Press the button again to change the display to the desired unit of measurement. After approximately four seconds of inactivity, the new unit will be locked in and the compass/temperature display will return. If an abnormal temperature reading is displayed for an extended period of time, see your dealer/retailer. Under certain circumstances, a delay in updating the temperature is normal. Compass Calibration The compass may need calibration if one of the following occurs: • After approximately five seconds, the display does not show a compass heading, N for North, for example, there may be a strong magnetic field interfering with the compass. Such interference may be caused by a magnetic antenna mount, magnetic note pad holder, or a similar magnetic item. • The compass does not display the correct heading and the compass zone variance is set correctly. In order to calibrate, CAL must be displayed in the mirror compass windows. If CAL is not displayed, push the on/off button for approximately 12 seconds or until CAL is displayed. 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. Automatic Dimming Mirror Operation The automatic dimming mirror comes on each time the ignition is turned to start. To turn the automatic dimming feature off or back on, press the on/off button. The indicator light on the mirror is lit when the automatic dimming feature is on. Compass Variance 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 the vehicle is outside of zone eight. Under certain circumstances, as during a long distance cross-country trip, it will be necessary to adjust for compass variance. 2-50