Do you have anything tied into the fuse box? Ascessories? Sounds like a short to ground. What I would do is first make sure you have the correct size amperage fuse in the fuse box. Check the conector pin fit on the alternator. Check the ground wire on the alternator casing/shell. Also if you can or need to get a eletrical schmatic and start there. And did you ever unplug and plug back in the alternator? Sometimes just touching it fixes the problem. thats just my theroy. Could have been a terminal not all the way in on one or more of the pins.