This coach is 7 yrs. old. and probably has never had the fluid in the reservoir changed out. That needs to be done. Condensation can build up in there and contaminate. This is a PM item.
But this problem sounds to me like an electrical problem as others have said. It's a gas coach so you can easily put a piece of cardboard under the coach, crawl under there and clean every electrical connection then spray on some contact protectant—including the ground wire— and make sure wiring connections are tight. Then test.
If the problem persists, pull the control panel off the dash and check all those connections too for good contact, any corrosion etc, etc.
Whenever trouble shooting anything, always do the common, simple things first to eliminate those possibilities. If those don't do the trick, then you can dig further into other possible causes. I always use the saying, "you have to get thru the no's to get to the yes's.
Traveling Full Timers
Escapees, Maintenance Freak