I have a 2012 Sorrento SX and have been having mulitple problems with head units. I have been to the dealer 6 times and they have replaced my head unit 5 times because Nav didn't work, then rear camera didn't work, then radio would power off. I have had a KIA engineer work on this car and still having problems. KIA wants to fix it yet again and I'm now going to "Lemon Law". Has anyone had simular problems?