Did you ever figure out what happened? I have the same problem with my 2015 MKZ. I can play the THX demo and it sounds great; however, everything else only gives me sound from the front speakers. Please let me know if you solved this problem. [email protected]After a few failed attempts to fix the old amplifier I caved and bought a new one. I have sound again! Problem is that only the front speakers work. No sound coming out of the rear speakers. If I adjust the fade / balance controls to the rear the sound disappears entirely.
I remember seeing another post about someone that had to take it back to the dealer for reprogramming to get sound out of all speakers. I have a Forscan device but information on the MKC seems to be limited. Does anyone have any idea what needs to be reprogrammed? Thanks!
Edit: I just installed the latest update for Sync, but still no rear speakers.