One of the not exactly jokes I like to make is this: Many RVers have a few screws loose... And for the record those are the very screws I'm talking about.
When my rig was like a month or two old I had problems with the A/Cs.. sometimes the front one would work, sometimes the rear, sometimes both or neither.
One of the screws holding the wires to the branch circuit breaker took over TWO FULL TURNS before I begain to feel resistance,, Several of the other screws (All 3 colors) were loose as well. I re-tightened.. VERY TIGHT.