So I just traded in the HEMI for a 2500 Cummins and I need to hook up a 7 pin trailer
connector. (I can't believe they sell the 2500 without a towing package!!)

Anyway, the HEMI had the towing package so it was easy to hook up the brake controller
since the harnes was under the dash and all the wires were already run to the rear.

The new truck has the same harness under the dash to plug the brake controller in to, which
is nice. What about the other wires that go to the 7 pin connector in the rear?

Whcih wires go all the way to the back and which ones will I need to install?

Thanks!