Congrats Rog, I love my F150, I'm sure you will love yours. I am on my third one. And honestly if you are only going to haul a pop-up you may not need a different wiring harness. The pop-up I had just had the 4 pin. And that looks just like my transmission cooler so I would say that is what it is. You should be able to carry your cart, passengers, and a pup no problem. Shoot, when we had our pup, we towed it with our Pontiac Aztek a few times, and it has 3.4 v6 and a 3500# tow rating.