I have a 91 Explorer XLT with power mirrors. The mirrors won't move with commands from the arm rest controller, but the will move freely by hand. I can hear the motor inside running, but no movement. The mirrors stay put when you move them by hand and I can't feel the motor trying to push them in any direction. Does anyone have any experience or ideas on what has come undone. Both mirrors are the same. I have no problem pulling them apart.