If you crawl under the back of the jeep, look up, with your back on the ground. You should see a wire with a large round plug on the underside of the vehicle back drivers side corner. Essentially in line with the spare tire, but obviously out side of the vehicle. It will have a cap on it. All you have to do is remove that cap, and it will plug directly into the 5 way/7way plug that goes into the trailer hitch. Once it is installed, plug something into it that you know the lights work. See if it works. I have heard of some that do. But most, including me, had to go to the dealer and ask them to flash the computer to activate the trailer brake lights. IT is not hard to install the hitch either. If you can turn a wrench you are better off doing it on your own and saving the 800 dolllars the dealer wants to install.
Current: '14 Grand Cherokee Laredo 4x4. Gone '12 JK Sport 2 door 6 speed, '08 Liberty