Instrument panel fuse blown

The fuse for my instrument panel in my truck (a 1989 k1500 with the TBI 350) keeps on blowing when I turn on the lights while driving. I can put the fuse in and turn the key to the on position and turn the lights on and off all day without blowing the fuse, but if I turn on my lights while driving, the fuse will blow immediately. When it blows the instrument cluster lights go out and so does the electronic HVAC controls display. When you turn the lights off, the display reappears. I was wondering if someone else has had the same problem and could lend me a hand with this. I'd really appreciate it, thanks.

I am almost positive my instrument cluster (MPH, FUEL, ETC) wire runs to the radio. I have a 1988 Chevy K5 Blazer. I first tried to run it to the 12v wire because i figured it needs power, it blew the radio fues. The fuse kept blowing, so i ran it to the interior lights wire in my radio and it has been working fine.

That's my best guess