[MandK]

Jack, look to see if you have this set up like mine.
1) Inverter cut off in battery bay.

2) transfer switch that plugs into the inverter. It is usually mounted on the ceiling of the pass-through compartment right after the inverter. It plugs into the inverter with a standard 110v plug.

3);The remote switch in Tony’s top photo above. Mine is located in the cabinet above the coffee bar. If you do have this switch, just turning on the cut off in the battery bay will not turn on the inverter, you have to turn on the remote switch. Turn them on and leave them on. There is no reason to turn off the inverter until you are putting the rig in storage or will be disconnecting your shore power cord and not pulling with your truck plugged in.
My truck has no problem keeping the batteries at 100% while towing with the GE fridge running on it’s normal settings running off of the inverter. We have the same year and model trailer.