Disengage Surge Brakes

I would appreciate help on how to automatically disengage the surge brakes on my trailer when backing up. My understanding is that they are supposed to disengage when they get an electrical signal from the backing lights on the Armada. Unfortunately, even on the big tow package, it appears Nissan did not enable this signal on the connector. Anyone else dealt with this problem? Do I need to run a wire from the backing lights to the connector or is there an easier fix?