I had this issue on my 2015 DS. I think it was only one button that would not illuminate. Air recirculate button I think. Had to get a complete new module. Luckily I had purchased the LR extended warranty so I was not out of pocket for the repairs. I don’t know how the module works or how it’s designed but surely it is possible to repair/replace a single LED. Perhaps an independent workshop or auto electrician could check this out?Has anyone come to a conclusion with the lights failing? Or is it, as mentioned, a complete new module?