Car won't shut off

Since we have no idea how it's wired, I have no clue. Do you use a relay to power the ignition/ charging circuits? What do you have for an alternator setup? If for example this is a three wire GM and you have it wired with no diode, resistor or lamp in the no1 exitation terminal, those can fail the internal diode trio and cause a feedback circuit much like that.
Thought I would bring this thread back to life, since I have the same issue in my Scamp. I use a starter relay and a three wire alternator. My question to this post, is how do I confirm that there's a diode, resistor, or lamp as described? I'm fairly ignorant to electrical components.