take the wire coming from the mid single, and snip the wire leading to the switch in half, and to the ground in half.
get a double throw double push switch, and attatch the 2 wires coming directly from the pickup to their own middle prong.
then attach 4 wires, to the other 4 prongs.
then attach the top right, and bottom left together, and top left and bottom right together. solder all the wires to the prongs, and then attatch the wire that you sniped leading to the switch to the top right-bottom left, and solder, then attatch the ground to the top left-bottom right, and solder. attatch the switch to the guitar. i did this by drilling a hole through the plastic cover over the electronics, making sure it was long enough for the switch to move completely, and then screwing it in.
if you have a humbucker in the bridge, then if you flip the switch, your guitar will now have the bottom thre pickups in series and will have a massively cool sound similiar to a fender. if you have three singles, by flipping the switch, you will have instaled a switch that goes from 2 singles to a humbucker. cool huh?
if you need help, or any other wiring advice email me. <firstname.lastname@example.org>
here is a sipmle wiring diagram
NOTE: if there is a plus, then it means that the 2 wires are connected, otherwise donot connect them
+----->to the pickup middle wire
+-----+ | +-------+
| | | | \------>to ground
| - - - <-\(dpdt)| wire
| - - - (switch)|
| | +--|---------/->to pickup ground
+-----------+-------->to pickup selector