So I had this used unit installed in my infinity. When I go into Ipod mode it plays the music from my ipod but the head unit doesn't take over so I can control it from the head unit. The head unit screen reads "Disconnected". I have to select the music i want to play next from my Ipod, although it does take over the volume function, in other words if i change the volume on my Ipod it has no effect. Can someone tell me whats wrong?