I've got an intermittent (now mostly not working) issue with the BTA connection between the NXD-505 head unit and my phone. The connection works just fine for control - I can reliably start and stop the play action on the music player from the head unit - but there is no audio coming out of the system. i.e. I can see the time counter moving, but nothing is heard. Tried different phones, disconnected / reconnected bluetooth on the phone, rebooted the phone, turned off/on the head unit, etc. No joy. The Rocklin SC swapped out one of the modules (not sure which), and that seemed to fix it for a while, then it started getting flakey again after a few weeks. Now it's pretty much not working at all, though sometimes it works after a bit of driving. A possible clue is that I hear a periodic "thump" in the audio system every few minutes, like the head unit was trying to reset the BTA adapter after a timeout. (Ok, so that's the software engineer in me speaking - pure conjecture). Once I noticed that there was a momentary "hands-free device connected" message on the phone about the time of a thump. Bluetooth itself is a digital signalling mechanism, so I'm guessing that there is either a set of audio lines between the BTA adapter and the head unit, or perhaps some sort of digital audio bus. I talked to the SC service manager (an old time Roadster tech), and he said that the modules are all in a chain, he thought with the iPod one first, then BTA, then Sirius, so perhaps the iPod module is flakey. According to the installation manual for the head unit, the first one should be BTA, so perhaps they've got it wired wrong? He said I could try to take out the iPod one (I don't need it anyway), and see if it helps. Is the audio electrically passed through from one module to the next (such that a faulty module would break the audio chain), or is the cabling separate for each (separate wires in the bundle), which would indicate a broken cable? Oh, also, the Sirius module seems to have dropped out of the selection ring (FM / HDD / BTA / iPod are present, but not Sirius), so depending on where it is in the chain might add a clue. Before I start digging into the car, any ideas where I should be looking first?