I have an in dash navigation system in my car (Pioneer Avic 940bt if it's helpful) and I used to be able to plug in my iphone 4 and play music from it, but for whatever reason I haven't been able to for the past 6-9months (I've just been using my iphone 5s and bluetooth audio) but I'd like to be able to navigate through music easier than reaching in my pocket so I'm trying to figure it out. I can plug it in, it'll be connected and I can search through my music via the dash screen and click to play a song and it'll start to play it but without any sound. It will let me know how far into the song I am etc. but nothing actually comes out of the speakers.