battery isolator wiring - 78 chieftain 440 motor

[wreckless17]

I have problem I recently noticed corrosion in battery compartment so I took batteries out and cleaned them and the whole compartment then I noticed a couple of broken circuit breakers so I got new ones when I was swapping them out I disconnected the wires from the battery isolator and not sure which wire goes where everything works inside but I don't think the batteries are isolated like when I drive the rocker switch could be on single battery but it appears that both batteries are being charged thank u for any advice anyone might offer

[DaveVA78Chieftain]

Typical battery isolator setup



Dave