Probably need some more info. If you plug it in to shore power what happens? Is the chassis battery being charged by the engine generator? I’m not familiar with your coach, so I am not sure if you have a BCC or BIM or BIRD and what is supposed to be charging when you are under engine, generator or shore power. If shore power charges the coach batteries, then it may be in the generator to converter/charger line. There is a circuit breaker between the two that sometimes trips.
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