hey guys my order is still processing but i have a quick question. My blackouts were installed in emg wiring. So i assumer because they were active that the pickups were not grounded. I pulled out all the electronics and switches and the only thing that was left was a mysterious wire coming out of the body that was heat wrapped at the end so no wire was visible, it was a black wire. Is this the what needs to be ground to the volume pot or do i need to get a seperate wire to do that?