2 field terminal alt with the blue wire feeding it switched 12V & the green wire pulled off of the other alt male terminal & it is full fielding? If so then what Nacho said, an alt problem. (if not holler back). eyeball the brush assys for any visual grounding then pull the blue wire off of the other alt male field terminal & ohm both the male alt field terminals to the nearby case & there should be NO continuity (& ohm em to each other). You might take the brushes/holders off & inspect/reinstall (something hot is touching ground). the field circuit is improperly dead shorted to ground makeing it full field. Do not let it FF for more than a few seconds at a time, just long enough to see if each of your corrective procedures is fixing it. & have all lights/accessories off during this