I have a 2004 f250. Bought used with no owners manual. My trailer brakes quit working. I went to ford dealer and got the fuse diagram. Fuses are good. I switched brake controllers and still no luck. I know the brakes work on my trailer cause my buddy used it with his truck and had no problem. The deal said there is a relay for trailer brakes but could not or would not tell me the location of it. Any ideas????? I'm out of options other then taking it to someone to work on it.