Chevrolet 2001 Tahoe Owner's Manual page 128

Electrochromic Mirror Operation
The right side of the button, labeled TEMP and located
at the bottom of the mirror, turns the electrochromic
mirror on and off. An indicator light, located to the
right of the TEMP button, will come on when the
electrochromic mirror is turned on. To turn the mirror
on, press and hold the TEMP button for 15 seconds.
To turn the mirror off, press and hold the TEMP button
for 15 seconds. The indicator light will turn off.
Compass Operation
With the ignition on, the compass will show two character
boxes. The mirror will display the compass heading.
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.
2-50
Compass Calibration
The compass may need calibration if:
D
After 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.
D
The compass does not display the correct heading
and the compass zone variance is set correctly.
In order to calibrate, the letters "CAL" must be displayed
in the mirror compass windows. If "CAL" is not
displayed, push in the "COMP" button for approximately
eight seconds or until the letter "CAL" is displayed.
The compass can be calibrated in one of two ways:
D
Drive the vehicle in circles at five mph (8 km/h) or
less until the display reads a direction, or
D
Drive the vehicle on your everyday routine and after
several turns the compass will become calibrated and
will display a direction.