Classic Car Circuit Breakers

One of the most common questions I get from a lot of beginning car guys is, you know I've got a problem with this electrical circuit on my car and I can't find the fuse box anywhere in the whole car. And, really what it comes down to is, fuse boxes didn't even exist in cars until, you know, starting in the early 1960s. So most cars, you know, 1950s and older, are going to have what they call circuit breakers. Well, they're going to have two kinds of protections. There are circuit breakers and inline fuses. Some items will be inline fuses, like if your car has a clock or a radio, there may be an inline fuse. And, you know, I'm sure most of you guys are familiar with those. And those are usually the tube electrical type, or tube glass tube type where they come apart and there's little fuse inside. So there are a few circuits that are protected by fuses, but for the majority of cars, like even this '57 DeSoto back here, you know, it's protected by three main circuit breakers, and the circuit breakers in the car, you know, aren't, you know... This is actually the circuit breaker out of that car for the power seat track. And, the way the circuit breaker works is, if there's a short or it becomes overloaded, where normally a fuse would blow, the circuit breaker pops but then automatically resets itself. There are a couple of different kinds of circuit breakers out there. There are some where you have to manually reset. They have a push button or something that you have to reset, but for most car years, you'll see this auto reset type. Now with that said, over time, they can get too sensitive or they can snap openers without, so, and not return. So it's a good idea when you're restoring a car, like this car back here, is to replace these circuit breakers with new ones. You know, the new ones look a lot like the old ones, and, you know, can pretty much, fit in with them. They're all rated. If you look at your fuse blocks there'll be like this one here, is rated for a 20 amp fuse. And that tells us that at 20 amps, it will blow, it'll pop. And when I say it resets itself, you know usually they'll reset themselves almost instantly. So they'll like pop. They'll go pop on, off on, off, on, off. And I've had a case where, like, I wired a circuit wrong and they pop the circuit breaker, and then all of a sudden my interior lights were popping on and off and on and off, and I knew right away that something, I had a short somewhere that was causing the circuit breaker to pop. So then that's a good time to just, you know pull the battery, go check your wiring, or pull your hot lead off your, the ground lead off your battery, and then you can go find that find your fault fix, or, you know repair what's actually causing the short condition and not try to just keep overworking your circuit breakers. So, and when you get back into the '30s a lot of the '30s cars, you know you'll find that, like, the circuit breakers may not look like this little block here. They, they sometimes, you know, I know like 30s, mid-30s Fords, it's a big block that's usually up behind the instrument panel and, you know, you've got to go hunting, finding it, but just it's a matter of doing, you know, some basic electrical circuit tests and find out what blown and why it's not working and isolating that circuit breaker. And you can certainly replace that original circuit breaker with a more modern design too. Just, because it's under the dash you're not going to give up all that much in authenticity. Yet, you'll have the convenience of knowing you can go to the hardware store, go to the auto part store and get a new circuit breaker for your car. So, before you start looking for that fuse box consider your car may be old enough that it has circuit breakers instead.