Power gear slides use current sensors in the control box. Not switches.. The theory is when the slide is all the way in or out the motor will "Stall" the current draw by the motor will thus INCREASE and the controller will then shut off.
Your problem indicates a bad control module.. Sorry I can not be more specific.
I do believe there IS an adjustment but since I've yet to find my Power gear control module.. I can not be sure.
OH, something else.. IF that is a rack and pinion slide (Long toothed rail)
You may want to pick up a dozen bolts 1/4 inch, Grade 8, Also some washers and NYLOCK nuts,, the bolt should be long enough that the SMOOTH portion of the shank is longer than the distance across the SQUARE shaft (the large of the two)
WHen a bolt shears replacem, make sure the SMOOTH part is visible on the thread end, then washer up to the threads and NYLOCK it down tight.