Folks, thank you for the quick responses.
As to the tech, yeah I have lost faith in him. He was walking me through why he was replacing the parts, but now he’s as lost as I am so I think his knowledge may be limited. Haven’t found a mobile replacement for him so I may have to pull the camper. It’s a bit of a hassle to do that though so I’m trying other options.
The battery I did not check the water levels, but I did need to move that. Should have said in the beginning it was the original battery, and it sat for about probably 18 months unused. Do to my own negligence, I should have at least had a trickle charger in it, b didn’t. The new one appears to work fine, the fan for the converter isn’t on constantly anyway.
The other stuff I will try out. Again thanks for the input folks, we shall see what my meter skills find.