2003 mountain Aire air ride dump valve location

The valve should be right by the tanks, which should be up front about under the drivers seat location.

Having said that, be sure to check your air bags too. Based on the age of the unot you may have a slow leak in one of those.

You will have 3 of them, one for the rear axle and one at each front wheel. If all 3 are going down close to the same rate, you most likely have bags that are dry rotted and need to be replaced, especially if they are the originals. Is the air in the tanks is going down as well when the engine is shut down, the leaking bags will continue to deplete the air supply until the bags go flat.

Based on my experience with my Dutch Star on a Spartan chassis I would suspect the ride height valves berore the dump valve.

Those are the ones that there are three of. Two front and one rear. I haven't replaced one for a few years now, but did replace several and found them at a heavy truck parts supply house. Price then was about $50 +/- and they were a pretty easy job to replace.