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?