Well... I dunno about the stock system... but nearly all aftermarket Stereo's have a cell phone interupt input for an interupt. They all feature that you connect the phone to the stereo... and then the stereo mutes out when a call comes in and the call is broadcast over the stereo's normal speakers; I would assume the stock bose setup is the same. So it probably uses some or all of the bose speakers for the phone interupt

 

The real question is...

Anyone have a "blueprint" or "schematic" of the wiring that goes to this speaker, or any real "easy way" to access it?

 

possibly with the bentley manual. I'll check teh wiring diagrams tonight if I get a chance.