i have a 1996 f250, about 2 weeeks ago it started blowing fuses which knock out the running lights and instrument pannel lights. i have checked all the wiring from front to back and can find no shorts. but when i replace the fuse's and oull the switch out to turn the lights on, the fuse blows again, or sometimes i get a few miles down the road before it blows. does anyone have any ideas?

 

Have you recently put a aftermarket radio in it? Could have something shorted there. Could be a bad headlight switch.