If the speedometer works it indicates you are getting a signal. You can purchase a junk yard instrument panel. If a new vehicle even the Ford dealer isn't permitted to work on them. In the Atlanta Ga area this company is licensed.
http://www.speedometerservice.com/ In your area I'm unsure.
You have to sign an affadivid stating mileage at time of trouble and estimated mileage at repair. This is so you have an accurate mileage on the title.
If your speedometer works give age and engine size of vehicle.