There are numerous posts on similar issues on this forum. If you indeed have the SurgeGuard, that would be the first place I would look. Take the cover off and tighten the screws that hold the circuit board in place. One of these screws also serves as a ground. These loose screws were the source of our customer's problem. We chased this same intermittant problem for several hours trying to not only duplicate it, but perform the necessary voltage checks in the brief second that the power was gone. Hopefully this is the source of your problem and you won't have the same hair-pulling episodes we went thru!! To all else who may have the Surgeguard installed, we were told by the manufacturer that this was a common problem that they had seen numerous times with that product. Please be sure to unplug the coach before diving into this project!!! Best of luck!!