well I would start with the fuse and then the switch. because the only thing that makes a motor go back and forth or up and down is reversing the polarity. so when you hit the switch down,..then that would be negative polarity and up would be positive polarity so with that being said the "up" part of the switch is probably bad. understand ? so yes, check fuse then switch then motor , the motor has the same concept except the problem may be in the switch not the motor and vice versa. I hope I didn't confuse you. get back if you need clarification