2012 Expy XLT. Need to install trailer brake controller. I have the 4 way at the back but want a 6 or 7 way. I see a bundle marked brake at the back and it is not connected. Does this imply that I can mount a plug and play unit at the front? Appears I can't use the Ford OEM as my dash isn't properly designed to accommodate the unit. I would really prefer to install this myself. If I do, is it really necessary to have the computer flashed?