||02-02-2012 12:01 PM
With newer cars there are electronic speed signals. These signals also go to a cruise control if you have that? Is the cruise control working?
And the same signal may be used for shifting an automatic transmission. If automatic, it is shifting ok?
Other than that, did the Ford dealer say what was wrong? That a part needed to be replaced? If yes, then maybe you could replace that part yourself.
I would say there is a good chance it is an electronic problem with the speedometer. And you probably have to buy the whole instrument cluster. You could maybe find one at a wrecking yard for not too much. Just be sure it is for the same model car with the same features. Some have different "indicators" and so forth for different options.
If you want to troubleshoot it first, you would need to know electronic testing and have a factory service manual set of books. That would include an electrical diagrams manual. The set of books cost $150 and can be ordered from a dealer. Or alldata.com
There could be some other problem. Like a short in a wire somewhere. If that is the case, you would need to troubleshoot the wiring to find the problem.