Powered portable system

New to the forum, so thank you ahead of time.

I’m attempting to build a portable air horn setup. I would like to be able to move the set of horns via a portable box I have built. This would allow me to use them in alternate locations, as that’s what I desire. I want to be able to use it in my truck bed, golf cart, or in the field with a deep cycle battery.

I have a set of Nathan P5’s with a 5 gallon tank and a Viair 400C compressor. I bought the Hornblasters 540 air kit. I’m going to be operating them with a manual valve.

A couple of questions.

I understand the basic wiring of positive and ground. However, my challenge is the blue wire coming from the pressure switch. Where would I be able to hook this up too? It’s normally for the “on” side of the ignition. In the instructions, it’s not clear if I can hook this to the positive post of a battery. Would this work or am I going to mess up the switch? Or, could I use a “hot” wire connection via my trailer hitch connection outlet?
Speaking of that, I suspect the wiring for the trailer hitch connection is not big enough for the current that’s needed for the compressor, correct?
I would really like to avoid tearing into my ignition console of my truck, just to get another wire in there.

Any suggestions would be appreciated.

I wired the blue to the positive of the battery via a 5A fuse, worked for me. Hot wire from trailer hitch should also work, but I would also add a fuse.

The Viair 400C pulls 28A, I don’t know your hitch connection, but I guess it would blow the fuse or melt some wires.

Another option would be to use add-a-fuse to get a switched plus.

Thank you!