I have a new 2016 Chevy Tahoe with the trailering package, but it does not have the integrated trailer brake controller system built in the dash as a part of the cluster that contains the headlight dial and the control dial for 2WD-4WD. Can the cluster with the integrated trailer brake controller system in it be purchased separately and added in place of the one that doesn't have the brake controller? My salesman says it cannot be ordered, but that seems a little crazy since it is simply plug and play!?@#!