2003 GMC Sierra 1500 Pickup Owner's Manual - Page 141

3. Keep pressing the on/off button until the desired zone number appears in the display. Release the button. After approximately four seconds of inactivity, the new zone number will be locked in and the comp/temp display will return. 4. Calibrate the compass as described below. Passenger Air Bag Indicator Your vehicle may be equipped with a passenger air bag indicator, on the mirror glass, just above the buttons. If your vehicle has this feature, the mirror will display the word ON, or an air bag symbol in Canada, when the passenger air bag is engaged. For more information, see Passenger Sensing System on page 1-74. 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 in one of two ways: Drive the vehicle in circles at 5 mph (8 km/h) or less until the display reads a direction, or 0 drive the vehicle on your everyday routine and after several turns the compass will become calibrated and will display a direction. 2-54 Cleaning the Mirror When cleaning the mirror, use a paper towel or similar material dampened with glass cleaner. Do not spray glass cleaner directly on the mirror as that may cause the liquid cleaner to enter the mirror housing. Automatic Dimming Rearview Mirror with Compass and Temperature Display If your vehicle is equipped with an electrochromic mirror, it will, when on, automatically dim to the proper level to minimize glare from lights behind you after dark. The mirror also includes a displayin the upper right corner of the mirror face. The compass reading and the outside temperature will both appear in the display at the same time. The dual display can beturned on or off by briefly pressing either the TEMP or the COMP button.