Originally Posted by kcheves

I just installed the same hitch and harness a couple of weeks ago, you can find my post about it here. Link

The OEM harness adds an AHM module to your car, which installs into the fuse panel in the rear hatch area. When you code the car, you need to add this module to the car's build order (VO) so that it will be recognized. Carly cannot change the VO, you'll need to use real programming tools for this. And not doing the coding is not an option, because the brake lights won't work through the tow hitch connector until the vehicle has been coded.

In addition to the dealer or Indys, there are various services that will code your car remotely for you. I was quoted $205, and decided to learn how to do it myself instead. I've been spending the last 2 weeks gathering the information, tools, and cables to do this myself. Getting all the software (which is in German!) is the hard part, but if you are good with computers its all do-able. Go to the beginners lounge at www.bmwcoding.com for more info.