Bob, while you're trying to locate the issue, make sure you take a few minutes and find the large ground (bare solid wire) that comes off the power bay and is screwed to the frame. I started tripping my GFI a few months ago and couldn't locate the issue. I removed and cleaned the wire and frame and remounted the ground. No problems since.
Don & Mary
2019 Newmar Dutch Star 4018 (Freightliner)
2019 Ford Raptor