As you know, your Solar system keeps your leisure (or what are known as COACH) batteries charged. And, If you are plugged into a campsite power connector this power source does the same thing for you.
Your symptoms of having the; interior dc lights, dc temperature control panel, fridge and dc water pump not working would normally mean that your Leisure batteries are not charged.
Because of this contradiction, I need to as do you have a DC Cut-Off switch that in larger motorhomes is used to disconnect the batteries when your Rv is in storage? Many people will forget about this switch and not turn it back ON, for use. If that isn't the problem the next most likely problem could be your MAIN DC Fuse might be blown. And then there is always the possibility that your batteries are really not charged or may even have a loose connection in the wiring?