You know what a lowest common denominator is and most of us are exactly the same, in at least one subject matter, so you are not alone. One of mine is that I don’t know your coach specific systems, but we will try to help anyway.
You said the gen runs your AC and DC loads OK. I expect your use/store switch is on to allow batteries to charge. What happens when you turn off the gen (with no AC shore power connected)....... do you still have your DC lights powered from the coach batteries? If not, you might have a tripped 50 amp re-settable breaker that is usually in series between the converter 12vdc output and the use/store latching relay connected to the coach batteries. The re-settable breaker is usually under the bed near the converter on many coaches.
You may also have a problem with the use/store latching relay. Do you hear a latching relay operating and releasing when using the use/store switch? Attaching a “generic schematic” showing this typical 50 amp re-settable breaker and the latching relay between converter and coach batteries to give you a rough idea of a basic battery set up. Also a picture showing what the small 50 amp resettable breaker looks like.
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