A couple of years ago my power tongue jack quit working. I decided to use the crank for the rest of the summer. I took my trailer into the shop just before Thanksgiving. I told the service writer of the problem and also a couple of other issues. He walked outside with me looked at the jack reached under the trailer pulled the jack wire out took the fuse out wiped the ends and put it back in. Much to my amazement it has worked ever since. I did not know there was a fuse there and I just think of all the cranking I did that summer, I learned my lesson.