Well the B72 is plugged in correctly, though I want to verify the pins and wires are seated right. I don't like how much weight/stress the rest of the harness is putting on that. I wish the layout was different or that I had figured out a way to adjust it. I guess I'll have to make some support for it for my own peace of mind.

I'll continue chasing down the line. I like the suggestion about the front-to-rear harness (I'm assuming B99 to R3). Any idea what those look like or where they are? I found B1 and B2 recently but B3 wasn't nearby.

Thanks all for the input!!