In addition to fuses, some circuits have fusible links. Fusible links are wires of a smaller gauge than the ones they protect. This allows them to literally burn up before enough current is generated to do damage to the items they protect. So fusible links look just like a wire. They are thicker than the wires they protect because of their insulation which allows them to burn out without starting a fire. In my car, they were bright orange and were located off of the main wiring junction box next to the battery. Again, they were big thick bright orange wires. They were replaced on my car, so I am not sure if they are the same color on stock fieros.
Any how, in my car the previous owner spliced the stereo and some other extra electronics directly to one of the fusible links. When I replaced the stereo with a more powerful model, it blew the link and I lost power to the radio, cluster, and a few other items. I must have spent an hour on the fuse box until I decided to check the battery. When I went to look at the battery, I found one of the fusible links burned in two.
The repair was simple I just had to splice in another fusible link. It cost like $1.50 at the auto parts store. However, I spent a good two hours rewiring the stereo and other items to go through the fuse box properly!
So, you are looking for some thick wires which are burnt in two on the main wiring harness near the battery. Perhaps another forum member can verify what they look like when not replaced?
I hope it is something simple like this. Good luck!