OEM 7-pin wiring

I have recently purchased an OEM hitch receiver and plug. I am looking to wire up the 7-pin plug as OEM as possible. I know there is a separate harness for the trailer plug, that I assume runs up to the engine bay. However I have seen things about certain trucks not having a 23P conenctor to plug into. Does anyone know anything about this connector, or where it is located? If I have to wire things up myself, I can but I'd rather just buy the harness if at all possible.

Also, I'd assume I don't have the pigtail in the cabin for the brake controller as well correct?

 

I checked there, there is loom but no open connector. I need the harness that goes from the pigtail up to the front of the truck.

after a little more research, i sounds like there is a different harness that will give you a 4 pin and is readily available from a dealer. At $150 though it would be much easier to go with an aftermarket harness. I can run 12v to the back myself and wire up the brake controller later if I ever need to.