mankk Air Pressure Switch 70-100 PSI Thread 1/4" NPT 24V 12V DC Air Compressor Pressure Switch for Air Horn Train 70-100-1/4" NPT-W

I’m like 99% sure the upfitter switch is powered and grounded from the factory. Basically there’s a bundle of wires under the hood that runs into the cab to the switch panel. It’s intended for accessories to be added easily. I need to look back into that because I actually tested it with a voltmeter earlier and wasn’t getting signal but I can’t remember if I had the switch flipped on at that time or not. link for pressure switch My use case is for airing up my tires after driving on the beach but I’m sure that air horns could be wired somehow if I added a tank somewhere in line