Originally Posted by jiris248
There are no limit switches. It works on an "overload" principle. If the system detects a high current indicating the window is not moving freerly (at any position), it will stop the motor. Your problem do can be mechanical, but I would more suspect the motor (brushes). If they are worn, the motor works intermitently. If you shake it a bit, the brushes my make a temporary contact and the window finishes its travel. Then the motor stops again.
ditto....also spray some pure silicone where glass travels in tracks up and down.