The black and red plugs connect to the trailer controller module that you need to purchase if you don't have the hitch option. If you take off the interior access panel at the right rear and look up you'll see the red plug. Link below is the part except for 2015 the part number ends in "J" not M. Dealer will require the Vin #
I have 2017 cayenne base. had a curt hitch put on all fine. wiring is turning out to be a nightmare. I have the porsche plug (958-612-506-00) but my mechanic says the 'module' in the car is missing and he cant plug one of the wiring boxes into the car becasue of that.. anyone know if this is correct and what is missing? suncoast says they have a module but its not needed on 2017?