My Atwood died once on our previous coach, and it turned out to be the "thermal cutoff switch," which isn't a switch at all, but looks more like an inline fuse. In mine, it was connected to a brown wire on both ands and the thermal cutoff itself was covered by a clear plastic tube. I was able to disconnect it, bring to Camping World, and they sold me two new ones. It is also possible to remove your motherboard too, and CW was able to test mine. But... beware... they told me mine failed the test but it really was quite fine. So apparently the method of testing the motherboard isn't straightforward enough for at least that guy to give a correct read.
2013 Fleetwood Discovery 40G, Cummins ISL,Freightliner Chassis, Allison 3000.
2009 Jeep Wrangler Unlimited Toad w/ Blue Ox Aventa tow bar and M&G Braking System