If you handy you can try taking the motor off (watch your fingers!) and take it apart to clean the rotor and brushes. They can get carbon build up creating a bad connection internally which the controller senses as a high amperage draw and stops the motor thinking it reached full extension or retraction. Could also be the controller but trying to clean the motor first is free. This was the problem on my 2 step model and has been working flawlessly since I cleaned it. A light metal grade sandpaper works great to remove the carbon build up. Battling with the motor magnets on reassembly can be a little tricky. Good luck
