I have an Atwood Model 8535-IV furnace in my 5th wheel camper and sometimes the fan doesn't shut off after the

Hi: Rick............Thank you for coming to Just Answer with your question. My name is Randall and perhaps I can assist you with this issue.

This is usually a sign of the relay on the board having burned contacts and they stick. If this is a later version of this furnace this has been a problem. The solution is a new control board. I recommend one by Dinosaur Electronics if you need one. That is a "Fan 50 Plus" board if you have the later model board. Testing on this sort of problem gives varies results and sometimes are inconclusive. It can be sticking contacts in the thermostat as well if you have an old style unit. Go HERE for the Service Manual on this unit. I would print out a copy for your use as there is a lot of great information in there. Get back to me if you need more help with this. Follow up questions are included in our fee. R.J.