Upper Electronic Module (UEM) (2005-2014): Design: Compass: Notes

The compass is integrated in the rear view mirror. The compass display is integrated in the mirror glass. The display is a vacuum-fluorescent type. The display luminance is regulated via the internal light sensor in the rear view mirror. When the vehicle is started, all the segments light up in the display. All the segments then go out after a couple of seconds. The display then functions normally. The compass has a button (1) which is used to:

• set the magnetic zone in which the car is being driven
• calibrate the compass.

Magnetic zones 

In many places, magnetic north is different from true north. In order to compensate for this difference, the compass uses a method that divides the globe into 15 different zones. If the compass is not set for the zone in which the vehicle is being driven, it may display the wrong direction. If the vehicle is transported between different zones, the magnetic zone setting must be altered manually.

The correct zone must be selected for the compass to work correctly.

1. Ignition position II.
2. Hold the button on the reverse of the rear view mirror in for approximately 3 seconds until ZONE is displayed (use, for example, a straightened paperclip) The number for the actual area is displayed.
3. Press the button repeatedly until the number for the relevant geographical area is displayed.

The display reverts to the compass direction after a few seconds, this means that the zone change is complete.

Calibration 

Calibration of the compass is necessary for it to display the correct direction. During calibration, the compass detects the magnetic field from the vehicle, which must be taken into consideration when calculating the compass direction. If strong magnetic fields affect the compass, such as for example, an antenna close to the mirror, or if changes in direction occur too quickly, the compass shows the last measured direction until a new measurement is successful. The direction will not be updated if the vehicle is stationary.

The compass must be calibrated when: 

• the display does not show a compass direction within a couple of seconds. This may be due to a highly magnetic object, such as an antenna, being placed in the vicinity of the compass.
• the compass does not display the correct direction, even though the correct magnetic zone has been set.

The compass may need calibrating to display correctly. For best results, switch off all large power consumers such as interior lighting, blower fan, rear demist etc. and avoid having metal objects and magnetic objects near the mirror.

1. Stop the vehicle in a large open area with the engine running.
2. Hold the button on the reverse of the rear view mirror in until is displayed.
3. Drive slowly in a circle at no more than 8 km/h until disappears from the display. Calibration is complete.

Alternative calibration step: set off as normal, disappears from the display when calibration is complete.