Tail Lights and Dash Lights blowing fuse

Whenever I turn on the headlamps the tail light and dash lights go out and blows out the fuse. I have disconnected both tail lights and tried again, blew the fuse again. I traced the tail light wires from the rear to the fuse box and did not find any short in the wires. I was then thinking that perhaps it was the headlamp switch on the steering column but I have not replaced this yet. I have read that the instrument panel circuit board on these cars sometimes have problems with the solder going bad and wires coming loose. Is it possible for the short to be on the circuit board and the actual dash lights are causing the short to blow the fuse? I always assume its the tail lights but in this case it may not be.