[David and Teresa]

        In the front bay, passenger side of my coach, is where the switch to activate the 120v air compressor resides. There is a pressure switch that feeds 120v to a relay that feeds the air compressor. There is a loose white wire that was on the other side of this relay which is now not connected. It may look like it's connected in the photo, but it's loose. The set screws are rusted so I can't tell where it was connected. I bought a new base to re-wire this. Where does the loose wire connect. Please excuse me if I have component terms wrong.

[encantotom]

i have 526 and will look later this afternoon to see if i have the same setup

tom

[Richard]

Can you post an in focus shot of that relay?
And can you back out a bit and show the wires leading into it, the well pump switch, and the compressor?

[David and Teresa]

Here's a photo. I think it attaches to the opposite side across from the other wire.    

[Richard]

Here is what I can tell you about the setup, and I have never seen the relay you are showing.

The black (hot) and neutral (white) are wired into the well pump switch, the square D box to turn the pump on and off based on pressure. The square D box is a standard well pump switch. The other nondescript grey box is more interesting. It is a relay triggered by the HWH leveling system. It turns the compressor on. The interesting thing is the HWH switch is wired parallel to the well pump switch. Either will turn the compressor on. The HWH relay, being wired in parallel bypasses the well pump switch so that the compressor will provide maximum pressure. After all the well pump switch is ususally set at 90 psi cut out, which is not enough pressure to raise the rear of a the coach.

All that to say, find your hot and neutral wires. Wire them in parallel through the well pump switch and the HWH relay to power the compressor. Forget about that unidentified relay..

[David and Teresa]

I'm thinking the unidentified relay (on the right) goes to the device on the air tank that's in this bay. It blows out the water after the air compressor cuts off. Possible?

It hasn't worked in a while. I manually blow the water out of the tank since it stopped working.

David

[Richard]

Yes, that is very possible. Those auto drain setups are know malfunctions, and known leakers. IMHO, you are far better off with a ping tank and manual drain. You can install a nice stainless quarter turn valve on the tank and not fret with the petcock.