Ran across something interesting today. my brother in law was trying to tow a uhaul trailer with his 2014 Jeep Grand Cherokee today. the factory wiring harness was not functioning. after trying several trailer and vehicle combos they determined it was a problem with the jeep and not the trailer.
i searched around a bit and came upon several sources that claim you have to take the vehicle into the dealer, and have them re-flash the computer to enable the factory wiring harness. while this sounds like the dumbest thing i ever heard, apparently its true for 2014-2016 jeep grand Cherokees. i do not know if it extends to other Chrysler vehicles.
i found a stock 2014 file in the tune repository, but was not able to find a parameter anywhere that would allow that feature to be enabled. possibly something to add to HPT in the future?