No power except microwave when plugged into shore power

You have two posts going with the same subject matter but on two different forums. Might be better if you can get the moderator to combine them into one. That way you won't be posting pictures twice or answering the same question twice.

In my opinion, you need to start at the batteries and follow the 12v until it's there any more. Whatever is causing the problem will be between the last two measurements.

Good luck

Ron