Do it yourself. If your truck has the tow package, then you should have the 7 pin hookup. Get yourself a good brake controller. I use the Prodigy 2 brake controller. You can get a pigtail specifically for your truck from the Prodigy people. With a factory installed tow package, there usually is a plug-in under the dash for the brake controller pigtail. This way you don't have to splice into various wires under the dash to hook it up. If you have the 4 wire flat trailer plug in, trace the wires and find out where it plugs into underneath. There should be a second set of wires there with a "dummy plug". At least that is the way Ford does it. When I converted my former Ford van from 4 way flat to the 7 pin hookup, that is what I found. I bought the Ford 7 pin hookup. I unplugged the 4 way flat connector from the wiring harness and plugged in one pigtail from the 7 pin in its place. I removed the "dummy plug" from the other wiring harness (located next to the 4 way harness) and plugged in the other pigtail from the 7 pin unit. After that, I was good to go.
Hopefully the other truck manufacturers do their tow packages in a similar fashion. Hope this helps.
Bob