So today we were headed out for the week. I decided to take off the cover to look at the relays. Pretty simple as there were only 2 screws holding on the relay cover. Manually
actuated the armature numerous times. Since this ATS is basically new, everything looked pretty pristine inside. Put together a set of tools to take with in case surgery was required. Got to the campground and plugged in and no buzz. Everything worked fine. So either that fixed the problem, the problem is intermittent, or the threat of surgery scared it into working. Thanks all for your advice.