Assuming your ignition switch is working you probably have your alternator being excited by the ignition 12 volt power. Alternator keeps 12 volts on the coil side of the switch even after turning off the switch. Add an idiot light or other small resistance load in the excite wire and see if it fixes the problem. As stated, one needs to develop an understanding of automotive wiring or find someone that can fix these kind of problems. There are plenty of good books on the subject. I once watched a hot rod burn from bad wiring choices, it is not worth it.
