Ok did some digging,
I apologize for the misinformation previously stated.
The large white wire runs from the 80A engine fuse, around the front of the radiator and was connected to the terminal marked "A" on the isolator, no splicing.
By the terminal "CB" I meant "Coach Battery" so I'm pretty sure that was wired right.
The 3 wires coming off the plug on the alternator are unmolested and run to a factory loom.
I'm just hung up on why there was a "bubba" run wire from the top nut of isolator to 12v positive. It should really be a switched 12v source , correct?
So would the switched 12v source wire be one of the 3 wires coming out of the Alternator plug?