A lensatic compass has a sighting lens and a floating dial for precise navigation, while a mirror compass has a mirror for sighting and a fixed dial for general direction. Lensatic compasses are more accurate but require more skill to use, while mirror compasses are easier to read but less precise.
it is because of the differences between the mirror's temperature and the air's temperature.
What fuse controls the mirror and compass and temperature in a 2003 Chevy tahoe
How do I go about restting the mirror-based compass in a 02 nissan Altima?
There's actually an on/off button for the temp/compass display on the mirror. It is the button located on the left front of the mirror itself. Push this and the display should turn on.
To calibrate the compass on an OnStar mirror, start by turning the ignition to the "On" position. Then, press and hold the compass calibration button located on the mirror until "CAL" or a direction (such as "N") appears on the display. Next, drive the vehicle in a circle at a speed of about 5 mph until the calibration is complete and the correct direction is displayed on the mirror.
check all of your fuses, recheck the connection on the back of the mirror.
That might be hard to answer. The vans never came with the compass in the mirror so its probably part of the conversion package. usually the mirror is tapped into the lighted visor circuit. Does anything else not work?
On my '97 Tahoe the owners manual has detailed instructions on how to reset the compass. This of course will only work with a compass mirror that has power. So does the mirror display directions but just incorrect or is there no display indicating that there is no power? The former can be cleared by selecting the region and driving around in circles a few times; the latter will require a little wire chasing or that you have a defective mirror module.
To reset a Bell mirror-mounted digital compass, you can usually press and hold a specific button on the device for a few seconds until the display resets. Refer to the user manual of your specific model for detailed instructions on how to reset the digital compass.
Nothing really, some top fit differences, some mirror changes, the rest were interior changes.
http://mojavetrail.webng.com/AutoDimMirror.pdf
your onwners manual will tell you how to reprogram the compass