Quit running while driving

There are multiple fuses related to the ignition switch. A simple trick to finding a short is to replace the blown fuse with a pair of spade terminals, then use small jumper wires to connect them to a twelve volt light bulb. A brake light bulb works well. When the circuit is live and the short is present, the bulb will be full brightness and hot so be sure it is not laying on the carpet or against a plastic door panel. Now you can unplug electrical connectors and move things around to see what makes the short go away. When it does, the bulb will get dim or go out.

You have an advantage when the short is always present. Intermittent shorts are much harder to find if they are not acting up while you are doing the diagnosis. If you see the test bulb get bright, observe if it stays bright, or if it goes out one second after turning on the ignition switch. That will tell us where to go next.