Electrical problem

Now you have two problems to fix, depending on what you mean by "fried". If there's a dead short, a 30 amp fuse will blow almost as quickly as a 15 amp fuse. If the circuit is simply overloaded with too many bulbs, that can eventually overheat the wires but it's not going to happen right away.

If a new 15 amp fuse blows, replace it with a pair of spade terminals, then use a pair of small jumper wires to connect them to a 12 volt light bulb. For a dead short, a brake light bulb works fine. When the circuit is turned on and the short is present, the bulb will be full brightness so don't lay it against a plastic door panel or on the carpet. Now you can unplug things and move wires around. When you do something to remove the short, the bulb will go out. If the other bulbs in the system start to work, your test bulb will just dim a little, but that's an indication the circuit will work when a new fuse is installed.

This test bulb works well for finding intermittent shorts too.