02 Tahoe OEM trailerbrake controller harn

Hey!

Just bought a used Tahoe to pull my travel trailer with. The owner's manual says the vehicle is equipped with a trailer brake controller harness. It shows a picture of it, but doesn't say where it is? Any help?  Thanks

they say that the trailer wiring is to the rear of the vehicle, or that the wiring for the actual controller is under the dash soemwhere? or both?