I just recently installed an alpine ilx-w650 in my 2008 limited with the factory boston acoustics system. Everything worked out great with the PAC steering wheel control harness, even after swapping the grey wires into the purple wire connectors in the harness to get the Bluetooth to work (thanks youtube!). My problem now is with the alpine head unit installed, the subwoofer does not work but when I plug the factory head unit back in the subwoofer works. I was hoping someone could point me in a direct to modify the factory subwoofer/amp to work with the aftermarket head unit or whatever I need to do or missed to make it work. I understand from many aftermarket system I've done in the past the alpine will have a dedicated RCA for the sub output and that will give the aftermarket amp the signal it needs. Is there a way to get that sub signal out of the alpine and into the factory amp? has anyone done this before or has a wiring diagram I use?? Thanks!