An amazing and worthwhile thing to do is to open your 12 volt panel. Take the cover off it so you can actually see the wires and the screw terminals to the wires, and most importantly the wires connected to the negative bus bar.
Use a good screwdriver to tighten all the screws. The ones to your problem will likely hold larger wires. If you can identify which wires might go to the slide out motors, remember you also need to identify which return wire comes back to the negative.
A great many problems come from loose wires, and your history with periodic problems often indicates an electrical loose connection. Try to identify the main feed wires from the converter. Tighten everything you can.
