Has anyone managed to program an IPhone to give voice directions via bluetooth? Apple Maps or Mapquest, same problem...the voice prompts work on the phone speaker, but not bluetooth. It's very hard to hear while driving.
Do you have USB? Can you connect it via USB? It might work if you do that. I am not sure about Apple Maps (in iOS 6), but with my Garmin app, USB connection works very nice! (I have iPhone 5 with iOS 6.)
Are you sure your radio it's set to Bluetooth? You'll know it's set up if you can hear music when you open a music file on the phone. It is not automatic. There are great instructions in the manual and voice prompts too when you push the talk button.
Other than that I can't help you, I have the superior Android phone.