Do you have the mechanical or electronic speedometer?
The standard speedometer is the mechanical one......a hard cable from the speedometer to the speed sensor that mechanically spins.
The speed sensor, from what I have read, has both a mechanical output (for the mechanical speedometer cable) and a electronic output (for the PCM).
My ScanGauge OBDII code reader give me a readout of the speed as the PCM sees it.
This is what is used by the cruise control.
So, most any shop can connect to the OBDII port.....drive the vehicle and see if there is a speed indication that can be read at the OBDII port.
Not sure if this link will work......part at rockauto
http://www.rockauto.com/catalog/x,ca...parttype,10634
The link is for the 2000 3.8L windstar.
I could be all wet on this one....as they list only 1 part for 2000 and for 1996, they list 1 for Electronic dash and a different one for Mechanical dash.........
However, what I said about being able to read the vehicle speed at the OBDII port with a capable reader still stands true.......the PCM needs to know the vehicle speed.
I understand that this part would be an easy replace....except for the location.....which makes it less than easy.
Now for the cruise control......don't forget to check the brake pressure switch on the bottom of the master cylinder......if leaking (damp or wet with brake fluid), it could be the cause of the cruise control issue......and can cause a fire.
Cheap and easy to fix.
For my 1996, the front wheel speed sensor is replaced by replacing the whole half shaft....not individually replacable.
The rear wheel sensor is replacable......bit of work but do-able as a individual part.