Hello, My name is Kevin but my friends call me Doc. I have a 2013 GTS with factory tow package which has the 7-pin receptacle. I am buying a trailer to haul DE car. The trailer has electric brakes. I recently asked the tech whether or not I needed to install a trailer brake controller or would the factory module apply trailer brakes whenever I apply vehicle brakes. I have also looked in the owners manual. Neither could answer the question. Any one know the answer? Thanks in advance for your help.