Pontiac 2004 Bonneville - Manual (Page 190)

Secondary Information
Center (SIC)
Electronic Compass
If your vehicle has a DIC,
it also is equipped with an
electronic compass. As
with all compasses,
this unit senses the earth’s
magnetic field to show
the direction the vehicle is
pointing.
The earth’s magnetic field is not always the same
direction as true north as we know it. So, you must enter
a zone number to tell the compass the difference
between magnetic and actual north. This tells the
compass where in the country you are driving.
The compass remembers your zone, so you only have to
change it if you drive to a new zone on the map. The
compass adjusts only a small amount for each zone, so
you may not notice a difference if you drive from one zone
to the next one, until you cross several zones.
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