Instrument lights fuse blown

Hello,

My 91 Century has a short circuit somewhere in the instrument panel wires because the instrument lights fuse blown everytime I change it. I have changed the headlight switch and dimmer switch and the problem stands. I´d appreciate if someone can advise me where can I find the wire diagram of the instrument panel so I can trace the problem or any other idea to detect where the problem is. Actually the fuse doesn`t blow so I think the line is definitely cutted.

Many Thanks in advance!!!...

"the instrument lights fuse blown everytime I change it"

"Actually the fuse doesn`t blow "

Which on is it, does it blow or not?

actually, no it doesn´t but at the beginning it did