Which rear harnesses do I need?

[davepl]

In my cab I have a 4-pin connector, lt grn, dk grn, brn and yellow if I recall. Two pins up and two sideways. I believe this is the rear body connector.

My old one was all cut up for trailing wiring, camper wiring, and who knows what else they added.

I've found the rear harness (MH 22075) but there's also listed an "intermediate" rear harness and I'm not sure what that is.

Does anyone know what all I need to wire from the under-dash connector all the way back to, and including, the tail lights?

Thanks!
Dave