Originally Posted by
WeirdBits
If you look carefully two of the wires should link to the eyelets, most likely black as negative and white as positive, and the third wire (probably the yellow) will connect to a tab of the chrome cover as the 'shield' wire. So, for a 4-way layout, your yellow would go to ground on the back of a pot and the black and white would go to the 4-way switch (assuming the colours are as I described).
If you are going to wire it as a standard 3-way Tele then the shield and negative both go to ground on the back of a pot and the
positive goes to the 3-way switch.