[prairieschooner]

Ours should be the same. We have to Air Ride Manifolds, one at the Rear of the coach at the engine bay forward and on the passenger side and one at the Forward storage bay just behind the driver's side steer tire. The Rear Manifold controls the Rear Air Ride and Leveling and the Front Manifold controls the Front Air Ride and Leveling. The Rear uses a Ride Height Valve on each side while the Front uses a single Ride Height Valve.
These Air Ride Valves are MAC and can be Manually Energized by using a probe through the center of the solenoid. I have been able to get these to work by probing them a few times in order to get any debris loose from the spool although I would see this as a temporary measure.
PS it could also be a bad Solenoid Valve.

I changed the all of the Rear Valves out a couple of years ago and all of the Front Valves out this year. If you decide to do this yourself take a picture of the manifold and wiring prior to disassembling it, I also made a drawing and keep it in a binder at the coach. It is much easier to get new brass nipples and use teflon tape. Use soap and water to ensure that there are no minor leaks after you get done. I tested my manifolds on the bench using a small air compressor prior to installing it. Not too big of a job if you are comfortable with plumbing.
Good Luck!
I was able to locate these valves online and here is the link;
Industrial Automation Leaders in Pneumatic Valves, Air Valves, Proportional Valves, Flow Controls, and Regulators