Here's one for you electrical whizzes. The passenger door power window in my 87 cab is a bit slow, but tolerable. However, when I push the switch in either direction for up or down, the only way anything moves is if I give the door panel a smack with the palm of my hand in the general area of where the motor bolts to the door frame. I went in and cleaned all the terminals, including the 3-wire bundle that is grounded to the frame, but it doesn't seem to make a difference. I'm wondering if it may be an internal fault in the motor itself. Any educated guesses?