I believe Joy will be hauling an Airstream trailer and one too large to even consider towing without the trailer brakes connected. My suggestion to Joy was to go with the Prodigy RF brake controller and don't mess up the interior of the X5 with a hardwired controller.

Joy: Don't even consider towing without the trailer brakes working. Regardless of what brake controller you use, spend some time in the parking lot adjusting the controller before you hit the road/highway. I like the to barely feel the trailer contributing to the overall braking effort.