Replace the fuse with a nail/rolled up fag packet foil/Stanley knife blade/nicely machined but 3mm thick lump of bar etc.
No actually, don't do that, it'll be horribly unsafe as I did actually point out on all the occasions I've found the above
One nail-fuse was on a Fire engine which in my mind made it worse still
As Rog and Bill say, clean it out, take a good look for chafed wires, bad connections and so on while you are at it and if that doesn't reveal the culprit you are looking at fitting bits anyway, so you might as well let a service centre with a tester do a full check.
Andy