Are fuses continuing to blow in your car? If you’ve ever owned a car, you’ve probably replaced a few fuses. I know I’ve replaced my fair share of them, but what do you do when your car keeps blowing out fuses?
When a car continually blows fuses, there could be an underlying issue going on. The fuse could be too small to hold the current, there could be an electrical short blowing out the fuse, or a component could malfunction. Other issues could be water damage or frayed, exposed wires causing the fuse to continually blow out.
While it’s easy and inexpensive to replace the occasional fuse, you don’t want to replace it every time you start your car. If you’re going through this problem, just sit back because we have the information you’ve been looking for right here.
What Is a Short Circuit?
While Short Circuit was a great movie from the 80s, we’re talking cars and electrical components today. A short circuit occurs when an electrical current flow through an unintended pathway.
Electricity likes to follow the path of least resistance, and with proper construction and installation, it will flow just where it is supposed to go. But if there are any loose wires, cracked insulation, or metal touching metal, the electric charge will try to ground itself out to get to the least resistance.
This results in a short circuit. Which in turn can result in a blown fuse. While we’re talking fuses, let’s see how much they may cost you, and how long they’re supposed to last.
How Much Does it Cost to Replace a Blown Fuse in a Car?
When purchasing fuses yourself, you won’t spend much at all. You can usually get multiple fuses for less than $10. There are vehicles that require specialty fuses that can definitely go up dramatically in price, but usually, fuses are cheap.
Even if you’ve never worked on a car before, you can replace your own fuses, and doing so will save you a lot of money. Most mechanic shops charge a minimal fee of about one hour of labor. This charge can be from $50 to $150.
When they are tasked with replacing a fuse, you will probably end up paying around $100 because of the minimum fee. So being able to replace your own fuses is a skill worth investing in.
How Long do Fuses Last?
I’ve had fuses last for decades in cars. Some manufacturers say their fuses last 20 to 40 years and even more. This being said, the auto industry recommends replacing your fuses every 10 years or so.
Older models may have glass tubes that don’t seem to last as long. The filaments inside are longer and sometimes the glass breaks. Plastic fuses with metal prongs tend to last much longer.
Reasons Why Your Fuse Keeps Blowing
When the jacket around a wire becomes exposed or the wire is damaged and frayed this can cause a short. It may not be enough to short out every time because vibrations may cause an intermittent short.
When the wire touches bare metal there’s a surge of electricity. This surge of power is enough to blow out a fuse. If you have to replace the same fuse over and over again but only intermittently, you may have a short in a wire somewhere.
Internal damage, debris, or moisture can cause an overload to sensitive circuits. This may cause more than normal current to flow to keep it working. The added power will end up overloading the circuit and causing a blown fuse.
Water is an excellent conductor of electricity. Whenever moisture gets into the electrical system of your vehicle, or it comes in contact with exposed wires, it will cause a short.
Most wires and electrical parts are protected from water exposure, but sometimes water finds its way in. Have you run over any large puddles lately? Did you drive through a heavy thunderstorm and now your car is blowing out fuses?
If so, check the electrical system, fuse box, or other areas for moisture and dry it out if you see any evidence of water.
Whenever you replace a fuse, make sure you put the same amperage in that you take out. The number should be printed on the fuse in a conspicuous area. On the colored two-pronged fuses the number is printed in white on the top. It should say 10A, 25A, etc.
The A stands for how many amps can safely travel through the filament before it burns out. If you put a 10 amp fuse where a 25 amp fuse was supposed to go, you’ll end up blowing out the smaller amp fuse often.
Now that we know why fuses burn out, let’s delve a little deeper into the issue.
What if My Fuses Keep Blowing Even After Replacement?
When you’re constantly replacing the same fuse over and over, you probably have a short somewhere or a malfunctioning part. Fuses are placed in your car to protect the sensitive wiring and other electrical components.
When a fuse blows it’s protecting your car’s electrical system from a surge of electricity. When it happens, it’s a good thing, because it’s doing its job and keeping you safe, though it can be a pain to replace them. As fuses continue to blow, you’ll need to find out why they do.
There’s a Malfunctioning Part
Over time motors wear down, and parts eventually degrade. A window motor for instance may have a short in it somewhere that blows the fuse when you use it. Replacing the bad motor will stop the fuse from blowing out each time.
Pay attention to which fuse is blowing out, as this could tell you where the problem is coming from. Your vehicle has fuses for all the electrical components from lights, to the fuel pump. I had one of these go out on me a long time ago.
There’s a Short Somewhere
Another reason you have to replace fuses constantly is because of a short circuit. A wire could be loose, or it could be cracked. Any time it hits something metal, it grounds itself, there’s a surge and a short that blows out the fuse.
You’ll have to find the short to keep from replacing fuses all the time. Here’s how you do that.
How to Find a Short Circuit in Your Car
Trying to find the short in your car can be a time-intensive job, even with the right tools. You’ll need your vehicle’s wiring diagram and a multimeter to test for continuity and amperage.
First, consult the wiring diagram to find out where all your fuses are. In some cars, you’ll have more than one fuse box, and possibly some inline fuses. Check all of these fuses and make sure none of them are blown. Replace them if they are.
If you have one certain fuse that continues to blow out, start there and inspect all the wires that come from that fuse. You’ll probably have to consult the wiring diagram to find out where all the wires go. First do a visual inspection to see if anything has come loose, or is damaged.
If you don’t see any physical damage, you’ll have to use your multimeter to find out where the short is coming from. This is where the process can get tedious. Most wires are hidden, covered in wire wrap, or tape that you’ll need to open to gain access to the wires.
Check each of the wires and even wire harnesses and sensors. Maybe there’s corrosion in a wiring harness or a loose connection. The repair usually isn’t very difficult, the hard part is finding the problem.
If that doesn’t reveal the problem, continue to check the components related to the fuse. It could be a motor that has failed or a circuit board somewhere that is causing your fuses to blow every time you start the car.
You may find the problem, and you may not. If you find yourself getting frustrated, or you don’t have the time to track down each wire and harness to find the short, you should take it to a professional.
Be aware that if they have to spend hours upon hours tracking down the problem, that time gets passed on to you. The positive is, they may have already experienced this issue and know how to fix it quickly.
It just depends on how much time or money you are willing to spend. Maybe you need time to save up the money to get it fixed. In that case, is it okay to drive with a blown fuse?
Can You Drive With a Blown Fuse?
Usually, you can drive your car with a blown fuse. When the fuse to my car’s fuel pump blew out, the fuel pump didn’t work so I couldn’t drive it anywhere. Most times, a blown fuse is related to lights, electronics, your stereo, or something non-vital.
If the fuse is related to the battery, or the charging system, you may end up stranded when you shut the car off and can’t start it again. You may have to jump start the car. Most times though, a blown fuse will not affect the operation of the car.
Can a Blown Fuse Stop Your Car From Running?
Not unless the fuse is related to a vital engine component. Most times though fuses are just related to accessories and are not the reason your car struggles to run. Rarely will a fuse prevent your car from running.
If a Fuse Blows Should You Buy a Bigger Fuse?
Putting a larger fuse in place of one that’s blown can have disastrous consequences. Fuses are safety features, and if you try to override them, you can burn out electrical components or even start a fire in your car.
Wires can overheat if you put a larger fuse in. They can melt and burn because the fuse would normally burn out and prevent the excess amount of electricity from flowing through.
You can go lower, though the fuse will usually blow out, you should never go larger than what is recommended.
When your car keeps blowing fuses you’ll have to find out why. Usually, there is a short somewhere in the car that is causing the blown fuses. It could be from moisture or water damage, a frayed, loose, or damaged wire, or you could have a component issue.
While it’s inexpensive and easy to replace fuses, you don’t want to replace them constantly. You’ll have to find the underlying cause, which means you may have to go over all the individual wires and connections to find the problem.
Be sure to never replace a fuse with a larger amperage as this can have devastating problems. Replace old, burned-out fuses with the same amperage.