[Richard]

Here is something to think about. On my coach, I have two battery bays also, but I only have one disconnect switch. My disconnect is on the negative side, but that point does not matter in the point I am going to make.

I have a positive lug in the upper right corner of the front battery bay. There are FOUR cables attached to that lug. They are the cable from the batteries in the front bay, the cable from the batteries in the rear bay, the cable that leads back to the merge switch in the rear panel at the engine, and the cable that is attached to the inverter.

The cable that leads to the merge switch is the pathway for all 12V to coach systems such as lights and Aquahot.

I know what you have is working. If I were in your situation, I would take the time when it is convenient, to disconnect all the positive cables at each end. I would then ohm them out to identify them with certainty. Labeling would be nice at the battery bay end.

Once labeled, you could then attach the cables in a configuration that would allow you to disconnect either battery bay, but still maintain the other bays connection to the inverter/charger and the merge switch. Right now, I am not sure you are wired that way. I'll draw you a sketch and post tomorrow when I'm not sleepy. Bank 1 needs to be attached directly to switch 1, bank 2 directly to switch 2, both switches, the merge cable, and the inverter/charger cable need to be connected after the switches. So you would actually have five cables on that lug.