I've used curcuit breakers that plug into the fuse box to help find a short in wiring...they'll let the current flow momentarily before they pop,allowing you to have a few seconds to try to locate any hot spots in the wiring where its shorted out,right after it pops--it'll re-set itself after it cools off...where as a fuse will blow instantly ,before you can even get your fingers off it!....
Some hacks just put a jumper wire in the fuse box and see if the wiring starts smoking where its shorted out..thats the quickest ,easiest way to find a short curcuit,but it might burn the harness up ,or the whole truck,so I dont reccomend that method...
A friend claims you can use an 1156 bulb and socket with the two wires plugged into the fuse box to aid in diagnosing shorts..though I have yet to try this method,he claims the light will stay lit as long as there is a short,and go out when you find and repair it...I've seen electricians use 100W light bulbs in old house fuse boxes to do the same thing,so I suppose it could work..
If the vehicle had a trailer hitch,I'd start there,looking at the harness and see if some butcher hacked it and spliced wires into it,often thats the most common spot for troubles to start...the dash lamps have a black ground wire that grounds up near the e-brake pedal,that might have gotten pulled off,and the dash might try to ground itself some other way,and blow fuses...then check all the light sockets,see if the correct bulbs are installed,I've seen more than one old truck that should have 1157 tail lamp bulbs with 2057 bulbs in one or more sockets,that will cause cross feed problems ,and if an 1157 has one filament blown and its touching the other one,it'll also cause a hard to diagnose condition too..
