I have installed a trailer hitch and BMW wiring harness on my 2007 X5. Hitch went on with no problems I found it pretty easy to do the hitch install. Got a Hidden Hitch that does not require any cutting on the facia. Hitch receiver actually comes out just under the facia. Also installed the BMW wiring harness. Install of the wiring harness also went well. However, I do not have any power to the trailer harness. I know they require a reprogram of the ECU. Is the reprogramming required in order for the wiring to work. I am reveiving no fault codes. Any help or insight would be appreciated. Also has anyone paid to have the coding done, if so how much?