Hi Carl and Susan!
Sitting here in Manitou Springs Colorado-pretty nice. Our park, Pikes Peak RV Park, is small but in the trees and by the creek.
Cool Beans..
I am glad you bought the pump, it will come in so handy. I used mine when we pulled into the first truck stop, aired my truck's air bags up, then the air ride air bags. When we got here, we aired up the leveling air bags under the tires. Sue aired up both bicycle tires as well.
OK, the pressure switch is a must. I think mine holds at 140#, I would have to look. The first tee is for that, then it goes to the air horn tank, it cycles on the pressure switch, (as you already figured out)
I stepped up the wire size one larger than the wire on the compressor, I think 10, can't remember. Go one size larger than you have as well, should be fine.
I used two relays, one off the fan on the heat, A/C motor, (it runs all the time when the motor is running, that relay powers the coil on the heavy duty relay, so there is light power draw on the fan. I fused it up under the hood, I will just pull the fuse if any problems, you could switch it.
You can add a small 10# air tank, mount it under the truck, and put a ball valve on it for more air capacity.
These compressors are so quick, I didn't do it.
Hope that helps, I'll find a picture of the wires under the hood and post it.
Good luck on this!
Ozz