dome lights not working, fuse, and where?

my roomie has a prob, we both have 98's but his inside lights aren't working, i think it's a fuse but we can't seem to find a fuse that is faulty. we haven't looked under the back seat for anything yet but thought you guys might have a clue. the problem started when he got the car, the dash lights didn't work, so he went and took the whole dash cluster apart, put it back together, and the inside lights still worked but the dash still didn't, he finaly went and checked the fuse.....duh, and soon after he changed the inside lights besides the dash lights died. i looked throught all the fuses inside next to the door and didn't see anything blown, what do you guys think?

check fuses under back seat

checked that today before i checked the forums, it was blown, trouble is, when i put a new one in....it blew. i think there is a wire somewhere getting grounded or something, where would there be a typical spot that there might be a exposed and grounded water or something like that. idk, any input?

bump