In a 2007 Lincoln MKZ which has the THX Navigation radio system....I'm trying to install a Bluetooth CAr Kit. I have been told that there isn't a car adapter available that connects the bluetooth system to the audio system. I want to mute all speakers when an incoming call takes place. In order to do this you need an adapter to connect to the car audio. The other way I'm told would be to put a relay (2 per speaker) to shut off the car speakers when a call comes in. This is costly and time consuming to locate and re-wire in a THX sound system. Is there any other way to find that mute wire in the car audio and make it work with out the adpater????