Fuse issues with glow plugs
 

I bought this 95 Silverado not running. I put a new starter in , lift pump and rewired the relay, relocated the new PMD , installed a new oil pressure switch and radio. I had it running for about 3weeks and then a new issue started with no glow plug light and engine will not run. The only fuse that blows is the horn. If I replace it with a new 10 amp fuse, the truck will start and run. No start when horn fuse is blown .
what does the horn fuse have to do with the glow plugs?