Operation CHARM: Car repair manuals for everyone.

Principles of Operation

PRINCIPLES OF OPERATION

The compass is self-calibrating. This eliminates the need to manually set the compass. If the compass is displaying a heading and not displaying C or CAL, the compass is in auto-calibration mode. In this mode, the compass automatically calibrates for changes in vehicle magnetics over the life of the vehicle. This auto-calibration mode assures the compass heading is always accurate.

A display of C or CAL indicates the compass requires calibration. The compass may temporarily display C or CAL if the vehicle characteristics have changed (carwash, collision or other factors). Compass adjustment is controlled by the COMP switch which provides access to the calibration and zone adjustment procedures.

Excessive magnetism in or near the vehicle may cause the compass to display ALL SEGMENTS. In order to distinguish between vehicle magnetics and surrounding magnetics, drive the vehicle to an area that is free from large metal objects. Cycling the ignition switch ON and OFF resets the compass. A display of ALL SEGMENTS within 20 seconds indicates excessive vehicle magnetism and the vehicle should be demagnetized. Refer to Vehicle Demagnetizing. Vehicle Demagnetizing