i am wondering if i have the trailer break controller in my truck. I have the 4 flat harness at the back but i have a fuse in the fuse box in the trailer break location. so do i only need to get the wiring harness for the 7 blade or do i need a aftermarket break controller?

 

if the trailer your gonna be towing elec brakes then you deffinitly gotta have a brake controller....your gonna need the 7 blade harnes anyways....i got a brake controller in my truck, cost me like $100 and took like 2 hrs to install cause i had to do some extra wiring to make it work right since i didn't have the trailer tow package on my truck....i did have the 4 flat and the fuse like you

 

ok thank you