You can get the wiring diagrams here but you have to pay at least $15 for a minimum two days access. Some of the drawings for a V have been posted on this site. Even with schematics much of the car's electrics are computer controlled through computer links, making easy interpretations less likely.
Missed this thread: Service Manuals, Owner Manuals, Wiring Diagrams, Service Bulletins - Helm Incorporated has the book under Prius.
