2002 Ford F-350 Super Duty VSS Signal

I found what appeared to be the right VSS wire but the unit says i'm doing 40 MPH when i'm really doing 20 they told me to get it at the PCM on the drivers side... That was a joke! So they aslo said at a small silver module (Speed control Module?) On the passangers side of the engine bay pin 3 gray/black. Well I found a pin 3 and there was a gray/black wire in it... But it throws my reading off... Maybe the unit was all finished downloading? The navigation unit is the brand new one from alpine. The tech dept said that the VSS wire is only needed to aid the navigation when traveling in large cities with big buildings and tunnels... Anyone ran into this problem with this truck? How can I fix it?

I'm not sure about how the Alpine works, but most Navs have a way of recalculating the VSS. Not all cars have the same pulse, and just a tire change can make it off. The Elcipse has a setting just for a tire change and learns all over again. This may take a few miles before it learns totally. Gray/black is a standard color for VSS in ford trucks, my guess is it is the correct wire...Mike M2

Tech Manager

CS Dealer Services