I had a switch like that. It was a plastic all weather box bolted to the permanent SMV bracket. I removed it when I expanded the electrics and got a 12V marine grade lighter socket with rubber cap to use for my 3PH sprayer. I also purchesd 12V cigarette lighter plugs designed to be waterproof when inserted in that receptacle. I wired the lighter adapter to the factory work lamp leads under the seat. I ran wires for two pair of 100W off road lamps U-bolted to the ROPS and ran all my wires in looms under the tractor pretty much along the paths of already present stock wires and mounted a new switch box on the lower bolts below where the manual chute rotator bracket would mount above it on the loader controller housing. I also expanded the fuse box to a weather proof 10 circuit with leads off the alternator to the extra circuits. I bought relays but have yet to put them on. I thought I could tap into the circuit for the factory work lamp wires and control the sprayer from the dash, however, this disabled the fuel solenoid shutoff and uinless that circuit was on, I couldn't shut off the tractpor. I have yet to finalize this project (a year later

) I am going to ditch the switch box completely as I saw someone that had tiny military waterproof toggles with rubber boots mounted through small holes right in the dash and am opting for this option when time presents itself. I would also prefer to have the off road lamps inoperable without the ignition on, yet have not figured out how.
Cheers