Panasonic DOES make Bluetooth adapters and a B/T adapter is wireless to devices such as cell phones and other hand held devices. But if the BMW is reasonably new it likely has Bluetooth capability built in to the audio/gps system etc. Many newer vehicles have these types of set ups, BMW and many more. Generally external b/t devices are powered, plugged into an accessory d/c port, similar to cigarette lighter but some input to a USB port in some cases, that is not the norm. Whatever you have must be hard wired somewhere but I tend to agree with you, I have a feeling it could be audio related. Be careful tearing into it though, don't screw it up, that is a SWEET RIDE!!!!! Cheers back at you..BTW when you figure it out be sure to post something, I'm pretty curious at this point.