GMC Hummer H3 2008 Owner's Handbook Manual page 117

Instrumentation and Controls
See "Compass Calibration" later in
this section for more information.
The compass may also need cali-
bration if it displays an incorrect
reading.
If an incorrect reading is displayed,
first check that the compass is set
to the correct variance zone. If it is,
the compass needs calibration.
See "Compass Variance" later in
this section for more information.
. . . 116
Compass Calibration
The compass is self-calibrating,
but if C or CAL appears, or if the
compass is acting erratically, you
can manually calibrate it.
Before calibrating the compass,
drive to an open area that is
magnetically clean or free of large
metallic objects such as high
tension power lines or large steel
buildings. Verify there are no
magnetised roof antennas, or any
other magnetised objects inside or
outside the vehicle near the mirror.
• In order to calibrate the com-
pass, C or CAL must appear in
the display. If it does not, press
the button until C or CAL
does appear (about fifteen
seconds).
• When it is safe to do so without
disturbing other drivers, slowly
drive your vehicle in a 360° cir-
cle at a speed of 8 km/h
(5 mph) or less, until the dis-
play reads a direction.