the power supply for the joystick circuit board is on the 6120 wire in the joystick harness. this is supplied thru a 15 amp fuse. the fuse should be the accessory fuse in the chassis fuse panel. not everyone uses that connection though.
there should also be a 10 amp fuse in the ground wire down by the pump ground connection.
if you have power to the fuse in the plate, check the power thru the switch to the circuit board. check for power to the three spring contact connections on top of the circuit board.
check the three springs on the underside of the plate. these may be bent out of position. make sure they straight up and down. next clean the contacts they make with the circuit board. use a pencil eraser. that works good. also clean the ring circuit board that the joystick makes contact with. these contacts get corroded sometimes. sorry to ramble, hope this helps