2000 f350 turn signals and hazards quit working inside and out fuse is good what could be wrong?

Have had this problem many times. It's one of two things for sure. The multifunction switch or the flasher/turn signal relay behind the dash are faulty. The relay is blue and is a dual functioning relay which means its 2 mechanical relays in one. One for the flashers and one for the turn signals. It even has a little circuit board inside that some times fries and one or the other won't work. If you take the relay apart you can typically see the burn marks on the circuit board. Good luck.