I had another question regarding the vacuum adjustment switch. The back of my switch has two vacuum inlets (or rather one in, one out) and a wire. ONE wire. Where does this go? Is it for illumination? How does the one wire cover power and ground? I currently have the switch mounted where the speaker dimmer was and would like to illuminate the switch if that's what the wire's for so where would I splice in to? Thanks so much.

The wire is fibre opitc.

Nick