Why does music output switch to bluetooth from the USB adaptor?
I have an iPhone 4S running 5.1.1 When I connect to my Volvo XC60 using a USB adaptor the device works fine and charges. But after about a minute the sound mutes. Same if I listen with ear buds while the phone is charging. Eventually I found that the device is switching the sound to bluetooth and I can listen if I select bluetooth in the car audio menu. But I lose control of the device from the car audio. If I turn the bluetooth off the music is fine but then I have no phone connection. Any suggestions how to fix?
iPhone 4S, iOS 5.1.1, Volvo XC60 audio system