i unhooked batery first and rehooking it was the last thing i might have shorted out the alternater wire to the battery but i dont think that would have any thing to do with it.

 

just for piece of mind try taking off the neg/ground wire at the block and reattaching it. sometimes it can just get alittle dirty between the bolt and the block. my friends bronco had this problem while we were on the road and every time we stopped we had to jiggle the wire near the block.