You will probably need to remove the instrument cluster and take off the lens to reset the gauge, or sometimes skaking it upside down will work.
December, 6, 2008 AT 8:27 PM
I have used a good magnet to fix my gauge. Hold it in front of the gague, then turn the magnet counter clockwise until the needle gets back to normal.
January, 1, 2009 AT 9:56 AM
I'd like to add to this solution. Suffered the same problem with my 2000 Park Avenue, and read on a few other websites that a very powerful (40-50 lbs.) Was required. Tried a 20 lb. Magnet and got nowhere. Then, one day fiddling with a little telescopic magnetic pickup tool, I found I could move the needle - by aiming at the base of the needle, not the tip - but not enough to swing the needle around.
Went to Home Depot and bought a package of 8 round, quarter sized magnets (about 3 bucks) that collectivelly couldn't have pulled more than about 3 lbs, stacked them, aimed at the base of the needle, and it swung around easily and quickly.