Hello all. I'm new to the forum after purchasing a 2015 2 wheeled drive Tahoe. It seems to have been orded with some king of tow package because of having tall rear springs and the round plug in the bumper for trailering. There isn't a factory trailer brake controller in the dash next to the headlight switch. I removed that panel and hooked to a holder is a plug with 10 pins not connected to anything but it has the wire harness attached. What would this plug be for?