I had a battery go bad in my wifes 2001 Town & Country and when I changed it, the speed O stopped working. It was pegged all the way to the opposite side. Went to a mechanic and he could not fix it. The dealer told me $90 to reset it. I looked around on the net and found how to do it.
You put the key in and leave in off possition. Hold the trip reset down for ten seconds and the lights will start flashing on the dashboard and all the lights, tachs and speedo will reset.
Thank God! I was 2 months out of inspection because of this.
Hope this helps someone.