2003 GMC Sierra 1500 Pickup Owner's Manual - Page 139

Mirrors Manual Rearview Mirror Pull the tab under the mirror toward you to reduce glare from headlamps behind you after dark. Push the tab away from you for normal daytime operation. r I Automatic Dimming Rearview Mirror with Onstar@,Compass and Temperature Display Your vehicle may have this feature. When on, an electrochromic mirror automatically dims to the proper level to minimize glare from lights behind you after dark. The mirror also includes a duel display in 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. (On/Off): This is the on/off button. Temperature and Compass Display Press the on/off button, located to the far left, briefly to turn the comp/temp display on or off. If the display reads CAL, you will need to calibrate the compass. For more information on calibration, see below. To adjust between Fahrenheit and Celsius do the following: 1. Press and hold the on/off button for approximately four seconds until either a flashingO 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 displaywill return. 2-52