01 F-250 VSS wire

I'm doing a navigation system in this vehicle. The problems I have are...when you look at the vehicle status the vehicle speed stays at 0mph. Not only that but it says I'm way in Penns. when I'm in Texas. I didn't know if that was part of the programming or not. But I used a grey/black wire under the hood right by the firewall. Anyone have any suggestion, or tips? I also tested this wire in AC and it flucuated with the vehicles speed as we drove it around the block so I thought it was the right one. Directechs also said it was that color but we all know they are not right all the time. But do I have something wrong, or is it in the programming?

I installed an N1 in my 01 Land Rover Discovery and found that if i connected the speed sensor wire the unit would not work.. ( no audio prompts, no coordinates, no tracking) when i disconnect the speed sensor the unit works. I've contacted Pioneer about this but they seem puzzled and had no answers. According to Ford the gray/black wire found under the drivers's fender is the VSS and should provide signal for your Navigation.

Quiet!