Is there a way to get the iPhone 5 to play music through the Bluetooth connection on my Chevy HHR? Phone works great for making calls even voxer plays through it but not the music player
As tarheel mentioned Bluetooth protocol for hands free calling is separate from the protocol for audio.
If your stereo does not support Bluetooth audio but does have a line in there are devices like the now old blackberry music gateway which will add the functionality you are looking for.