Cadillac 2003 Seville Owner's Manual page 97

Mirror Operation
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(On/Off): The on/off button is located on the lower
left side of the mirror face for the electrochromic
and compass functions of the rearview mirror.
To turn on the automatic dimming feature, press and hold
the on/off button for about three seconds. To turn off
automatic dimming, press and hold the on/off button for
about three seconds again. The indicator light will
illuminate when this feature is active. The automatic
dimming feature is active each time the vehicle is started.
Compass Operation
Press the on/off button once to turn the compass
on or off.
When the ignition and the compass feature are on, the
compass will show two character boxes for
approximately two seconds. After two seconds, the
mirror will display the compass heading.
Compass Calibration
If after two seconds, the display does not show a
compass heading (for example, N for North), 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. If the letter C should ever appear in
the compass window, the compass may need
calibration.
The mirror can be calibrated by driving the vehicle in
circles at 5 mph (8 km/h) or less until the display reads a
direction.
The compass can be placed in calibration mode
manually by pressing and holding the on/off button until
a C is shown in the compass display.
Compass Variance
The zone is set to zone eight upon leaving the factory.
It will be necessary to adjust the compass to
compensate for compass variance if you live outside
zone eight. Under certain circumstances, as during
a long distance cross-country trip, it will be necessary to
adjust for compass variance. Compass variance is
the difference between earth's magnetic north and true
geographic north. If not adjusted to account for
compass variance, your compass could give false
readings.
To adjust for compass variance do the following:
1. Find the current location and variance zone number
on the following zone map.
2. Press and hold the on/off button until a zone
number appears in the display.
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