There should be some form of circuit protection in the starter signal circuit. Typically if the starter were shorted in the solenoid windings you should have already discovered a blown fuse. You use the term shorted, I'm curious as to how you found out that the starter was shorted. What was the initial problem you had, before installing a new starter. I can't access my wiring diagrams until the morning, I will post which fuses to check at that time.
Okay, so all that I see on my diagram is that the fuse for the starter solenoid operation is the "main" fuse located in the engine compartment fuse block, should be an 80 or 100 amp fuse. If the fuse checks out okay, you may have a faulty ignition switch, but at this point, I would recommend having the vehicle diagnosed accurately at a professional shop.