I picked up an auto dimming mirror with compass and would like to know if anyone has calibration instructions for the compass. I was told it was from a GM product but looking at the wire colors at the connector, I don't think it was from a GM. I know pin 1 is +12V, pin 2 is GND and pin 3 is for reverse (to disable the auto dim when backing up). I don't care about this feature anyway so I'm just hooking up the first two wires.

The mirror has a three position switch about where the dim switch is on a standard mirror. The switch positions are OFF M (mirror) C/M (Compass/mirror)

There is also a reset button under the mirror which I'm thinking is for calibration of the compass. I had a compass mirror in a 91 Caprice and you had to push a button and then face the car in the other direction and push the button again. I'm thinking this mirror is a bit more sophisticated and calibration is easier. does anyone know how to calibrate it?
Thanks,
Tony

A quick search on Google says the compass works like the one in my Dodge truck. Go to an open area free of power lines such as a parking lot and drive in circles for 2 or 3 times.

From the internet website http://www.craigcentral.com/durango/mitomirror.asp

quote d) The instructions state that it may take up to an hour of use for the compass to calibrate, however I found it to be only a few minutes. You can "Force" the compass to calibrate manually. Find a big parking lot somewhere, press and hold the [COMP] button for 6 seconds until "C" is displayed. Now drive in three complete circles allowing 45 seconds for each circle (I don't know how critical that amount of time is since I didn't have to manually calibrate my compass). The instructions stop here, but presumably you would then press [COMP] again, or maybe do nothing at all. My guess is that by the time you get to the big parking lot the "Cal" indicator will have gond off anyway and you won't need to manually calibrate the compass.

[This message has been edited by topcat (edited 11-18-2010).]

Thanks for the help, guys. plus for both of you.