[whatsnewell]

Do you know what the manufacturer name is? Mine are MAC valves and they are blue, and they are still made. There are three for each wheel. One for ride height, or travel height, and one for up and one for down when in leveling mode. If you air the coach up and then spray soapy water on each valve you might be able to see which one(s) are leaking. I would suggest just replacing all of them.

If you have time, take a picture of the solenoid/valve cluster(s) and post it here.