So I bought a box of fuses yesterday and planned on doing a long tedious session of tracking down this short. The first thing I did was put a new fuse in and turn the ignition to ON and then checked the fuse to see if it was blowing then or when I actually went to crank it. Well the ON didn't blow the fuse, so I decided to crank it over and see. And wouldn't you know... the pickup fired right up and ran perfectly fine. I spent a bunch of time wiggling wires while it was running to see if I could replicate the short. But never could find it. In the process I did find a wire that had been chewed on by a mouse and there was copper exposed. When I wiggled it I touched it to ground and got some sparks, but didn't pop any fuses. I'm thinking the short probably came from some moisture in a connection somewhere and now that it dried out the shaft is gone... until it rains again. Well at least I have a box of 24 spare fuses now, so if it happens again I will be ready to troubleshoot. Now on to start a new thread about keeping mice out of vehicles.