How Do Fuses Work: Car Repair & Maintenance Tips

"Hi! I’m William Myers from Austin Subaru for Expert Village. We’re going to talk about fuses and what fuses do and where the fuse box is located and what exactly is a fuse. Now a fuse is a protected circuit and the fuse isn’t the circuit it’s just a protector in the circuit. Now this is the main fuse box and relay box and it says right on the top fuse and relay box and its got a little clip over here that you push in and you lift it up and if you look on the under side right here you can see what all the relays and all the fuses do and it’ll tell you what their amperage is, where they’re located at. Okay now what does a fuse actually do, as I said a fuse is part of the circuit and it’s the protector in the circuit, now this right here is a modern day fuse and if you can see you have two pins that are going to plug in, you’re going to have power on one side this is going to supply power to whatever electrical circuit it is and you’ll see if you look really close right in the center there’s a little piece of metal. Now if something shorts out that little metal burns through and the reason it burns through so that you don’t burn the wiring harness, you don’t cause more damage this is the protector in the circuit this is what they call pop, blow I have a blown fuse but this is what a fuse does it protects your circuit. So let’s say your cigarette lighter and your power mirrors don’t work okay that’s two big item that aren’t working, you might want to start looking at fuses first because well what’s the chance of my cigarette lighter and power mirrors going out, well the power mirrors and the cigarette lighters could be on the same fused circuit, so let’s say somebody put a penny inside the cigarette lighter and it shorts out, it’s going to pop the fuse."