So I am soo confused with this. I have a Yamaha RGX 121 ZL, and its a HB-SC-HB config. Each pick up has two wires...one is for the volume pot and one is for the selector switch. I have one random black wire which is the grounding wire. Now as far as I can remember it was attached to the part of the tremelo bridge where the springs are held. Where do I attach it to from there? A pot?

Thanks guys for the help!