I am trying to install a brake controller on my 2013 X5D. I have found lots of threads on brake controller wiring that refer to the OEM tow package wiring, which I don't have. I already have the trailer lighting solved/installed which provides me with a 4-way flat connector. I have a round 7 pin connector to install that will add the electric brake wire (along with the lights), and I have a Curt proportional controller ready to install. I need the brake signal to tell it when, well, I hit the brakes. If I had the towing package, the wiring harness would be there with that wire. But I don't have that.
All that's really needed is the +12V when I hit the brakes. I am not sure of the brake switch has that available, or if it's more of a switch for the computers, and I can't seem to find a wiring diagram. My thoughts turned to using the 3rd brake light (12V there for sure) for the sense, but can't seem to find that wiring either.
Any suggestions? Links to wiring for the brake pedal switches or 3rd tail light? I have an small RV lined up to rent in 2 days that has electric brakes. Didn't think it would be this complicated!
Thanks,
Steve
Last edited by stevel42; 09-08-2020 at 11:33 PM.
Thanks! It would appear that X14235 carries the auxiliary brake light power, I'll have to see if I can find that in the wiring bundle. Getting a +12V off the brake pedal switch doesn't seem possible.
Does anyone know of a reason why this wouldn't work? I am trying to add a brake controller (Curt Spectrum) and have everything I need but the brake signal to activate it. I have the hitch installed, a lighting kit that doesn't load down the circuits - just need to add the brake controller to be able to tow a trailer with electric brakes. I haven't been able to find any info on this approach - everything seems to use the BMW trailer wiring add on, which seems a pointless expense and install to do since I already have the lights done.
But I could be wrong, it's happened before...
Steve
Well, I had a deadline (trailer rental) and didn't have time to go down this path, so I bought a "Echo" Bluetooth controller that worked great. The Curt Spectrum goes back to Amazon. It would sure be nice to be able to tap into the center brake light and have a more permanent install.
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