Cluster Light Problem

I'm trying to get my 73 Duster back to where I can drive it again, but if it's not one little thing it's the other...
What's going on now is the number 5 fuse will blow as soon as I turn the parking lights on. I switched headlight switches (I have like 3) awhile back and then I had taillights, parking lights, and headlights, but no instrument panel lights, which I'm not real big on, but it's better than nothing. So the other day I try switching to another headlight switch to see if my problem's in there, but even switching back to the origonal one that was working for awhile leaves me with a blown fuse....
If anyone's come across this and can point me in the right direction, I'd appreciate it.
Thanks,
Jon