The green wire is connected to the bare wire and then soldered to the back of a pot to create a ground. Figure 1 shows how the hot wires connect to the 3-way blade switch for series wiring, and how the switch itself is configured.
Photo 4 illustrates how to connect the wires of a 4-conductor Duncan humbucker in a parallel configuration. As you can see, black and red are joined—they become the hot or primary lead. White and green are connected to the bare wire to become the ground, and all three are soldered to the back of a pot. The parallel wiring diagram for the 3-way switch is show in Figure 2.
By wiring the humbucker in parallel, we have connected the start of coil 1 to the finish of coil 2. For the ground, we have connected the finish of coil 1 to the start of coil 2 and both are joined to the bare wire.
Doing the deed. After removing the strings and pickguard, unsolder the pickup wires from the switch and pots, being careful not to overheat them. Separate the wires from each other with your soldering iron. Next, twist and solder the black and red wires together. Do the same for the green and white wires, and join them to the bare wire. Now solder the black and red to the input lug on the 3-way switch, and the green, white, and bare wires to the back of one of the pots.
That should do it. Put the pickguard back on, restring, and test out your new tones.
Obey Your Color CodesDifferent pickup manufacturers use different color codes for their 4-conductor humbuckers, so before you start brandishing that hot soldering iron, make sure you’ve got the right color codes and have figured out how to connect the wires. Here are a few parallel wiring combinations for several other popular pickup manufacturers.
- DiMarzio: Red and white are hot, black and green are ground.
- Gibson: Black and white are hot, green and red are ground.
- Jackson: Green and red are hot, white and black are ground.