The battery in the picture has frozen and cracked. Must be replaced and I would almost guarantee the other battery is not good. Sorry, but you will need to replace the two engine batteries. Don't know about the house batteries??
On the Aladdin in 2006 the wiring from the senders go to a Tank Interface module, which will be mounting on the ceiling of either the 2nd or third bay behind the fuel bay. You may need to remove the ceiling panel in the bay?? The easiest way to check the senders, is to once you find the Tank Interface Module, swap the gray tank and black tank RJ-11 plugs and see on the Aladdin display if the problem travels with the wire switch. This should lead you to if it is the harness or sender. I would suspect the sender???? I have attached a picture on the Tank Interface Module.
FYI-If it is the harness with RJ-11 plugs on each end, I am not sure if that is straight thru wiring on cross wiring. You should be able to see by inspecting each end of the plug. If it comes down to the Tank Interface Module, I have one that you could have for shipping costs.
