http://zilvia.net/f/showthread.php?t=605934
Get a multi meter...and check things...
what is voltage at battery
what is voltage output from ALT while running
what is voltage at fuse box when running and off
etc...track that shit down.
also make sure you correctly wired the ALT. you need both the sense and dummy wires.
make sure you dont ask how to do that, because its all over the mother fucking internet