Thanks all.
I think it all started when I had it plugged into my pool filter outlet. I had it plugged in for weeks. The ants formed a trail up the power cord and into the RV. I bombed it a couple of weeks ago and got rid of most of them. There are lots of dead ones in that transfer switch box as well as on the contacts themselves. The transfer switch is in a kitchen cabinet, but there's no food in the rig and there hasn't been for over 6 years. They're super tiny black ants.
Anyway, I'll clean the ants off the contacts :)