Brake controller for E70 experiences

[wsanchez]

I bought an E70 in January and to tow an Airstream 16' travel trailer which I picked up last week. The process of getting all set up to pull the trailer has been a bit less straightforward than I was hoping...

I got the BMW hitch installed at my dealer. I asked before they installed if it would control the brakes on the trailer and I was told it would. After I got my X5 back, still being told that the brakes thing would be fine, I looked here and got the installation manual, which makes it pretty clear that a brake controller is not part of the install.

My understanding is that the brake controller is a requirement for towing anything of much weight, so being told that it's there and then finding out that it isn't wasn't leaving me impressed.

So I went to a trailer vendor and they were skeptical about dealing with an X5, but poked around a bit and found that (unlike the E53, apparently), there is some useful wiring in the vehicle, so you don't have to tap into the brakes yourself, etc. This was very promising, but the connector is in the wiring compartment in the trunk (right side hatch).

Since the controller needs to be where the driver can reach it, that was not ideal placement. Unless an existing wiring harness runs up to the driver area, they'd have to pull off a lot of plastic to run one up there. Not being BMW folks, they thought that would be best done by BMW.

So I went back to the dealer, a bit grumpy due to feeling misled about the install, confirmed that no such harness exists. They weren't terribly interested in performing a "specialty" (non BMW parts) install, but I insisted that since they sold me a vehicle that claims to tow 6000' and then installing a hitch that claims to tow 6000', that I expect it to do so legally and safely, which means I need a brake controller.

So they agreed to run the wiring up to under the steering wheel, where the friendly trailer folks could install the controller.

At this point, I have a good setup with everything working well, but I just wasn't feeling the BMW love I was expecting after buying a swank ride with all the options, eh?

The upside if you can get the wiring up to the front, the rest is of the controller install is fairly easy.

I also noticed that the sticker that came with the hitch says not to use weight distribution equipment. The trailer came with a weight-distributing hitch, so I asked the trailer folks about it, and they have no clue why BMW would advise against using one; I'm told they reduce sway and are "1000 times safer."

Anyone know why BMW advises against using weight distribution with the E70 OEM hitch?