Anyone know how to fix this ?

I have a '98 which is a bit different, but I start by reseting the compass to your zone and then re-calibrating. On a '98 you hold down the compass button until a zone number appears. Once this happens let go of the compass button and start depressing it until your zone displays in the mirror. Once you have entered your zone, the compass is suppose to display a "C" for calibration. At this point just drive the car until it re-calibrates or find a parking lot and drive around in circles until it re-calibrates. I am assuming that this is the same for a 2000 STS.

If the display is still garbled, then check the mirror connections...

As for when the compas states 'C'.. Just driving it will not calibrate it... Unless you happen to make a few full circles.. Best bet it to drive in circles for a quick calibration.. Warning though.. Sometimes youll get dizzy..

MacK