Swoop, I cant thank you enough.

Put the new pot in. Had to play around with the pots for a while (4 Hours) but finally got everything centered. Unit steering now operating correctly. The unit will now self center on power up and the 2 LED's you mentioned did in fact light up. I really appreciate your help.

if you are getting any erratic readings from the wheel sensor (pot) then that is probably your problem. You should get a clean sweep on your meter when checking it from 0 to it's limit which should be 5k.
If you are going out of range on one end of that sweep that would explain why you are loosing it when turned fully in the one direction.
As for wire guidance the only part it interacts with the steering is when wire guidance is turned on it looks for the steer wheel's position and if not 'centered' it forces the system to turn the steering to 'center' when on the wire and initialized. When off the wire it should allow steering to operate normally.
Putting the new pot that you ordered on should fix the issue.

The proximity sensor on the steer wheel is the pot mounted there sensing the position of the wheel position. Some units have a circuit board mounted on top with position sensors but in this case it sounds like it is just a pot.

There is a proceedure for setting the steering center and straight travel but you will need the service manual to set this. It is rather involved and takes 2 people at one point.

One quick way to see if the wheel is straight though is to remove the cover on the EPS steering unit and check LED's 1 and 2. When the drive wheel is straight they both should be lit.
One part of the MDU pot setting check says to check wires 16-17 and 17-18 and both readings should be equal within 100ohms to be considered as centered.

Also tried setting pots at 2K ohms, same results.

Thanks Swoop,

In fact it is a Curtis controller. I have been working on this unit off and on for a few days. I checked the pot at the steering wheel. It is a 5K ohm pot as well as the pot at the steer motor. What puzzles me is why both pots only read up to 4K ohms. I went to radio shack and got a 5K ohm pot. It reads all the way up to 5K. Anyway, I set the steer wheel straight, set both pots at 2500 ohms. Tested repair, the steering loses itself when turned all the way to the left. Then have to start centering process all over again. It doesn't do it unless you turn the steering wheel all the way. I did notice the pot at the steering wheel doesn't turn smoothly. I have that pot on the way. I have checked all wiring. To my knowledge there is no proximity sensor on the drive unit. I looked all over the drive unit for one. It is my guess that the card/controller reads the position of the 2 pots?? Do you know if there is another process of setting the pots other than setting them in the middle? Another thing, this unit at one time was set up for wire guidance. Not sure if this could affect anything?

well according to the serial number you gave it's not a good number or is too old and is not in hyster's db. comes up as a bad number.

but based on the truck model i can guess this has a curtis controller in it? GE control codes are not in this format.
according to curtis that A5 01 could be a 501A which is listed in curtis's code list and is shown to be a steering control code.

MDU Prox Steer: Feedback sensor error.
it says to check MDU proximity sensor and wiring.