Need GM Service Bulletins and all other available information on flat towing my 2017 GMC 2500 HD 4x4. Do I have to disconnect both batteries? Is there another way that precludes having to disconnect the batteries without damaging the electrical system, running the battery/batteries down, or having to reprogram all electrical accessories, (radio, seats, etc.)
All I have found is the attached service bulletin on 2014 Sierra 1500 4x4.