Re: Looking for wiring diagram for BC Rich ST III
Hi rbilleaud, and welcome to the forum!
Typically when you find a three conductor humbucker, it has one positive, one negative, and one split wire. The split wire would take the place of the two finish wires on a four conductor humbucker... as if you had connected them together.
This split wire is used to shut off one coil or the other, depending on whether you have the switch connect it to ground or to hot (usually it is connected to ground, which shuts off the south coil). Just wire the switch so that the split wire is connected to ground in one position and not connected to anything in the other.
As for which wire is which, I am not sure... and i'm on my way to work right now so I wouldn't be able to look into it for several hours. Try doing and Internet search for BC Rich pickup wire colors and see what you come up with.
Good luck!