Ken-
I had a similar problem this winter when I was plugged into 50 amps and my LED display showed only 30. An RV dealer who owned that campground spent over an hour trying to determine what was going on. The next morning he sent on of his guys back to work on it again. The first thing he asked me was if all of my breakers were turned on. I said I felt so, but went back and checked again. I found that the breaker for my engine heater was turned off. As soon as I turned it on, the LED display showed 50 amps. He explained why (which I can't remember), but that took care of it. It's worth a check to see if you might have the same problem.
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