Ignition Fuse Blown??

[SC74]

I decided to take Jessica's bronco for a ride today. I loaded the dogs up and off we go. After about driving 4 or 5 miles the Bronco died. Fortunately I was turning into the neighborhood when this happened so help was close. I tried to start and the battery was drained. I called Jessica and she came and got me and the dogs - we came came back in the truck and she pulled me back to the house.

When we got back I hooked up the jumper cables to the truck. It turned and turned but no start. First thing I tried was starter fluid to see if it was a fuel issue - still no start. Then I checked for fire - none! I checked the fuse and it was blown! What would cause the ignition fuse to blow? I've got a DUI HEI distributor and Centech harness that has never had any issues so it's none of those 30+ year old wire gremlins.

Could this be battery related? My yellow top optima died over the winter so I trickle charged it about a month ago and crank it at least once every couple weeks. It started today without any problems, but why would the battery be dead when it shut off on me?

The water temp. gauge wasn't working either (autometer gauge - not the stock cluster) for some reason :banghead: My other gauges were working fine cratchhe: