Sounds like a short in the wiper motor or wiper switch. I would disconnect the electrical junction at the wiper switch and see if the wiper motor now switches off if so the switch is likely bad. You would need a wiring diagram to trouble shoot the electrical circuit. Autozone have some popular workshop manuals for free on line once you register (for free) on their website http://bit.ly/autozone_repair_info or there is a company that independent auto repair shops "buy" their information from that offer a very reasonable service to do it yourselvers. You can get a one week subscription or year subscription very cheap. The information is year make and model specific repair procedures, service bulletins, component locations, wiring diagrams ect.... great quality information same as the professionals have ,much better than generic workshop manuals from parts stores, much cheaper than the factory manual try http://bit.ly/mitchell_repair_manuals_online and get an online repair manual subscription.