Working on a friends 98 grand caravan 3.3L. He said it had trouble starting and was running rough, and eventually wouldn't start anymore. When I looked at the engine I noticed the serpentine belt was off/shredded and also the alternator pulley was seized. So I replaced the alternator and belt. When I went to reconnect the battery cables, I noticed a lot of sparking at the terminals. With the battery cables disconnected, I measure 0 ohms (short circuit) between the cables. Any idea where to start? I would think that this is related to the seized alternator pulley somehow ( in other words the seized pulley caused another problem which in turned resulted in a short somewhere)

What do you think?