My problem is - I want to change pickup configuration in my LP from H-H into H-S-H. The problem is, that I have gibson's lp-like 3-way switch - can I connect the additional single pickup into middle position of 3-way switch somehow or maybe I have to change something into wiring (5-way switch is needed? Another switch (with H-H on 1st and single pkcp on 2nd switch) Please, help me!
You'll need to rout a slot in the body between the humbuckers for the single coil, then drill through to the wiring cavity so the pup wires can go through to the volume/tone pots. Then you'll have to decide if you want to wire it to the volume pot of the bridge or neck pup, then the same with the tone controls. After that you'll need to replace the 3-way selector with a 5-way and wire all 3 pickups to it to acheive what you want (lots of options there) I'd say it's not worth the trouble. But if you really want to, that's a small portion of what you'll need to do.