I have a 2019 Heartland Trailrunner 27RKS. The furnace stopped igniting. Heartland technical support said I need to replace the sail switch. However, I can find no way to get to it. There's no access panel on the outside. There are two fake panels to get to it. But you don't room to open the top of the furnace. It looks like it will have to be removed. Any suggestion on how to do that? I've looked for youtube videos but can't seem to find any. This is setup in a permanent spot with a deck attached so I can't take it to a dealership. Any help would be greatly apricated.