Car: 1991 Ford Mustang LX 5.0/5 Speed

Does anyone have insight into an electrical problem I'm having.

My instrument panel illumination lights will not come on. They worked without a flaw up until I replaced my engine. I did not touch my passenger compartment except to install a short throw shifter. I can not see how I possibly mangled any wiring.

The #13 fuse that governs my instrument panel lights and ISO symbols is blowing out on me.

I tried installing a 10 amp fuse instead of the 5 amp that the owners manual calls for, but that blew, too. I did not attempt any higher amperage.

What are the ISO symbols that it refers to?

The #4 fuse also governs the instrument panel lights but that one does not blow out. It is a 15 amp.