99 P71 Speedometer/ Odometer not working

i just fixed the speed sensor so the trans inst bucking anymore and the car rides nice.. the only thing is, when the speed sensor went, the speedometer was jumping around, adn then it stopped working all together. someone said that there is a wire or wires in under the hood that relate to this problem. any suggestions?

I've had to remove the instrument panel. I went to a scrap yard and got the whole assembly. This is an item the dealer can't repair. In Atlanta only one shop is allowed to work on them. Then they certify mileage. If over 100,000 it doesn't matter much on the resale. I would just try to get a used unit with close to the same mileage. I assume you have an electric speedometer. You can ohm wires from the computer to the unit. You also have to give a estimate on the mileage put on the vehicle when it was defective. They do good work but aren't cheap.