Re: 540p wiring
This is H/S/S right? The center position is off, and the outer two positions are series HB & split coil. Problem is some of the IBZUSA pickups had 3 conductor and some had 4. I'd almost have to be there to read the pickup. But basically the center position will be off no matter what. It's an on/off/on switch. So no worries there, just hook the main series hot wire to one side, and then the coil junction (whether its 2 wires twisted together or one wire already junctioned back at the pickup) to the other side.