Update:
I had no luck trying to cross the number from the tag on the valve. Apparently Holiday Rambler put the sticker on the valve with a Wabco part number but it's not a Wabco valve and the number on the sticker doesn't come up on Wabco's site. Upon further inspection I found a part number embossed on the valve housing with the name Midland. I was able to take that info and find a new valve on Amazon which they call a Midland style KN20031. It's only 24.00 so likely be replacing it again sometime. Thanks to all for looking.