I believe the item that you are refering to is for speed sensative steering. Ford Motor company capps it variable assist power steering (VAPS). As you slow down, it increases the power assist. As you speed up, it does the opposite.
After researching for a while, I may have determined your problem. There is a "GEM" which stands for generic electronic module. It is located behind the fuse junction panel in the vehicle. You need to first check to see if the GEM will communicate with a scanner. If there is no communication, it's bad. If there is, it should give you diagnostic codes to identify where the problem is coming from. Also, check the GEM for any evidence that water has gotten to it from a leaking windshield. From what I have found, that could be a problem.
Here is a picture / schematic of the PS system. Also, I tried to upload a schematic of the wiring, but it was too small to read.
Let me know what you find.
Friday, June 11th, 2010 AT 11:22 PM