This site, I think, is best and most complete guitar wiring diagram site. Here you will find detail tutorial, description, explanation complete with illustration of related guitar wiring diagram being discussed.
This site discusses guitar wiring diagram in 6 pages. The first page contains explanation about guitar volume and tone controls wiring diagrams (Fender and Gibson), Single Pole Double Throw (SPDT) switch diagram which consists of SPDT center on switch and SPDT center off switch, 3 single coils wired in parallel and series wiring diagram, Humbuckers wiring diagram, Dimarzio Pickup wire colors, Seymour Duncan wire colors, phase reversal switch diagram.
The second page covers discussion on Strat™ type guitar (3 single coils) modification advantages and disadvantages, wolf wire ultra Strat™ schematics and how it works.
The following page discuss about stereo guitar wiring diagram two pickups wired in stereo (Single Pole Double Throw Center ON switch type), 2 Capacitor Tone Control schematics, 3 Pickup Guitar, 94 Sound Wiring Option, Variation on the 94 Sound Wiring Circuit and the configuration diagram, Phasing For All 3 Pickups.
The fourth page explains about guitar solo switch. Here you will find detail explanation about Solo Switch Circuit for a 1 Volume 1 Tone Control Guitar diagram and schematic, Solo Switch Circuit for Fender Stratocaster™ Type Guitars diagram, and Solo Switch Circuit for a 2 Volume 2 Tone Control Guitar.
The fifth page discuss about 2 Humbucker Guitar – Custom Wiring # I Funky Five Switching™ diagram and how it works. The last page explains about 2 Humbucker Guitar Custom Wiring II, Super Seven Switching™ diagram, switch instruction and switch arrangement.