Adam,

My bad. I had my brain working in reverse and was thinking the Norgren five port valve is ahead of the ride height valves.

I think that ride height valve you pictured has failed, and what appears to be happening is that it is leaking internally and air is escaping. The air in your airbags is trapped by the 5 port Norgren, so the bus remains as it was when you turned off the key, but the air in your aux system is the source of air that is leaking and that air is escaping through the valve.

Replace the valve and you are good to go. The valve shown appears to be the type Prevost used that has a built in delay before it functions. I suggest when you order the valve you make sure you get that type. The other type now used by Prevost is an instant acting valve and has a black plastic case. Personally, I like the type you have.

That is an easy fix, but you have to get under the coach. Please do not get under it unless you have it properly supported. To get the maximum height raise it up on the air bags and use good support under the chassis support points. There is plenty of room for you to slide around on your butt once you are in the area between the two front wheels. Did I say support the coach?

If you do not change the length of the rod that ties to the lever arm on the valve you will not have to adjust your ride height so the replacement will be a simple remove and replace. Don't forget to support the coach.

Jon