Well, It's a common problem on BMWs but my S hasn't had any issues like this. The part involved is often called the clock spring, it's gone through quite a few changes over the years and todays cars often include the stalks and other switches behind the steering wheel. Basically at it's heart, imagine wires glued to a plastic ribbon and wound many times like and old clock spring with on end connected to the fixed column and the other to the steering wheel. The idea is they don't break when you turn the wheel. Unfortunately they break :O I Just replaced one on a 2014 BMW 528 with your exact symptoms($1800).
Well, Having replaced mine 4 times and awaiting on service for the fifth, I can say its electronic, not mechanical. I now have two sets of controller buttons (left and right, with cable) that i got back when they replaced (out of warranty). Funny now that with my voice control button non functional, I can actually honk the horn and the voice control comes on, it would be comical if it weren't the fifth failure of steering wheel controls
Supposedly the entire steering wheel assembly, including the stalks, in my 2015 Model S was sourced from Daimler Benz (or from its parts suppliers). it certainly looked identical to the MB wheel and stalks of the day, so I did not doubt it was "from Mercedes." I wonder if the more recent hardware is from the same supplier. And either way, I wonder if the hardware is or was truly from DB or its suppliers, and if the Mercedes cars have had similar problems with failures. In my 40+ years owning Mercedes cars before I got this Tesla, I found the switchgear to hold up well, but not forever.
Did you ever this resolved? I switched out brand new steering modules w/ harness- no change. Then bought a used clock spring - no change.
