I ended up taking it to a local BMW shop (not the dealer) driver side switch control unit replaced, passenger side switch control replaced (loc control part of this unit), back passenger side loc control replaced. Also had corrosion issue with wire harness, but mechanic spliced to fix instead of new harness. Glad I took it in, I would have been working on this forever only to save a couple hundred bucks all said and done. These parts are pricy and I would not want to make use of used parts for this use.