Are you talking a stud in the fuse box, or on the switch?
check this
http://www.elcova.com/h2/details.html
and open the manual to section 5 - scroll and you will find all the fuses and what they do.
To me it sounds like a pos and neg are touching...like maybe in the guard lights. Either way the fuse blows because there is a problem. You can check the wires for voltage with a volt meter too...just some ideas, you may have already tried them. You didn't tap into your DRL power lead did you?