Continually blowing fuses for gauges
I have a '97 Grand Marquis, I bought the car last Feb. Last week the fuse for the analogue gauges (#13 on the instrument fuse panel) blew. It takes a 15A, but there was a 30A in there that the previous owner must have crammed in. So I replaced it with a 15A (as listed in the manual)....it lasted less than 5 minutes before it blew again... so we stuck a 20A in there...that lasted 3 days... now I've stuck another 30A in there because it's the only thing that seems to last, however, I'd like to figure out why the appropriate fuse burns out so quickly, instead of just cramming in highy fuses and causing a potential fire hazzard.
Any help that anyone can offer would be greatly appreciated. Thanks in advance!