Hummer 2003 H2 Owner's Manual page 135

Mirrors
Electrochromic Inside Rearview Mirror
with Compass and Temperature Display
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 dual 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.
Temperature and Compass Display
Press the COMP or TEMP button, 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 TEMP button for 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.
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