Chevrolet 2010 Corvette Convertible Owner's Manual page 136

Press once to turn the compass display on or off.
If after several seconds the display does not show a
compass heading, there may be a strong magnetic
field interfering with the compass. Interference can be
caused by a magnetic antenna mount, note pad holder
or similar object. If the letter C or CAL appears in the
compass window, the compass needs calibration.
Depending on the mirror, in order to calibrate, CAL must
be displayed in the mirror compass windows. If CAL is
not displayed, press
CAL is displayed.
If the compass has map lamps, it can be placed in
calibration mode by pressing and holding the left map
light button until a C appears on the compass display.
The mirror compass can be calibrated by driving the
vehicle in circles at 5 mph (8 km/h) or less until the
display reads a direction.
The mirror is set to zone eight. If you do not live in zone
eight or drive out of the area, the compass variance
needs to be changed to the appropriate zone.
3-40
for several seconds or until
To adjust for compass variance:
1. Find your current location and variance zone
number on the zone map that follows.
2. Press and hold
displays. The compass is now in zone mode.
3. Once the zone number displays, press
repeatedly until you reach the correct zone
number. Stop pressing
to normal operation.
until a Z and a zone number
and the mirror returns