remove the top plate and check the springs underneath.
these are the contacts for power to the joystick. make sure they are at 90 degrees from the plate. clean all the contact points and the ring inside the joystick with a pencil eraser to remove oxidation.
that switch is the same as any light switch the same size. nothing special.
buy at any rv store if they carry them in stock.
if you are blowing the fuse, you have a short in the harness somewhere.
i know that sounds obvious, but it could be a bad circuit board also.