'95 Grand Prix Alternator Problem?

i have kinda the same problem 95 grand prix 3100 it will start but only if you unplug the alternator it runs fine i first thought it was the crank sensor then you can unplug it and it runs it should not run at all.i have it narrowed to alternator but if you unplug it runs plugged dies.no security light stays on with the key. no remote start please help