Thx. Good info. Is your compressor on a switch or just let the pressure switch do it
The answer is yes - both.
The compressors themselves are wired straight (fused) to the battery, however the control wire which controls the relays (and runs through the pressure switch) is wired to the Aux switch. If the switch is ON, the system will fill to 150psi and turn off. I can leave the switch on and it takes care of itself (the aux switches are wired to ignition, so no worries when the truck isn't ON).
Does that make sense? I should mention that each of my compressors has a relay attached to it. So if you were to look at the setup you'd see two large gauge fused wires running from the battery to the rear of the truck - one to each compressor for ~40amp power. You'd also see a smaller wire running from one of the Aux leads under the hood and splitting at the rear of the truck to control both relays at the same time. Run all your wiring and air line at the same time if you can. The rigidity of the airline makes it slightly easier than the bendy wires. Just tape everything together as one unit.
I really like my setup because it's all invisible. I don't lose any bed space and it's been solid for a few years. You can hear/feel the compressors when they turn on - but I have some beefy (1/2hp I think?) compressors made for an air ride suspension. It isn't obnoxious though. You can hear them from outside much better and it doesn't take long to fill anyway. The system comes CLOSE to keeping up with the engine driven York compressor on my Jeep - with the Jeep idling at least, you still can't beat a York with an electric compressor, but for airing up tires it's great. The train horn was just a bonus!
