After being used for a long time, any vehicle components can be damaged to some extent. If you see some electrical issues in your car, then one of the first reasons to think about is a damaged fuse.
What are blown fuse in car symptoms and causes? How to fix them? Let’s follow us for more information.
What Are Blown Fuse In Car Symptoms?
The Electrical System Stops Working
One of the most obvious symptoms of blown fuse in car is that the car’s electrical systems stop working completely.
Interior and exterior lights, windshield wipers, turn signals, dashboard lights, etc., are all powered by electricity. If you see them go through a loss of power simultaneously, the fuse is definitely broken.
Black Streaks Appear Inside The Fuse
A blown fuse in a car usually has a black streak inside and is obscured by the outer fuse glass, so it is often slightly cloudy.
Also, if the fuse burns out and is badly damaged, the metal strips inside the fuse melt and stick to the surrounding glass.
You can search for its location to find out if a fuse has a black streak. Typically there will be two fuse boxes in each vehicle, one for the engine and one for the electrical system.
Some Parts Do Not Function Properly
If one or more components are shorted or not working, the fuse that controls their flow of electricity is probably damaged. For example, when the OBD2 has a blown fuse, it cannot determine exactly the overall electric power and functionality.
If one or more of the components below are not working properly or stop working, you can have the fuse checked:
- The system lights (dome light, brake light, etc.) are flashing, then do not light up
- Indicators on the dashboard do not light up when the car has a problem
- Radio does not work
- The window wiper does not move
- The climate control module does not heat (or cool) enough as usual
- Cooling fans/ air conditioning not cooling enough for the car interior
The Test Light Is Not Bright
An unbright test light is also one of the blown fuse symptoms. People often use a test light to check whether the car fuse is working properly.
First, you turn on the ignition and place the test light head on the fuse you think is broken. Continue to bring the probe of the test light to the other fuses.
If the bulb of the test light glows, then these fuses are still in a good working state and vice versa.
How To Check Car Fuses?
Step 1: First, you need to locate the fuse box. Usually, it will be found in the driver’s compartment, under the dashboard, or on the hood.
Step 2: Use a small plastic clip to pull out the fuse that needs to be checked.
Step 3: Turn on the multimeter by pressing the ON button. Turn the adjustment knob to the resistance scale.
Step 4: Connect the multimeter to the 2 probes. You can cross the 2 test leads together. If there is a beep, the multimeter is ready to work.
Step 5: Insert 2 probes into 2 pins of the fuse. The red probe connects to the positive pole, and the black tip attaches to the negative pole.
Step 6: If there is a beep or the resistance is low, the fuse will still work properly, and vice versa.
What Causes Blown Fuses In Cars?
Short Circuit
The main culprit behind a blown or bad fuse in car is an electrical short. There are 3 main causes of this short circuit: damaged or melted wire insulation, malfunctioning electrical device, and wet conductor.
Damaged Wire Insulation
Suppose one or more wires are worn and exposed; they can come into contact with external metal parts or ground. It will trigger an intermittent short circuit or a complete short circuit.
For example, if the wires of a headlight are worn out and exposed, you’ll soon detect a headlight blown fuse due to a short circuit.
Sometimes you find the systems in the car still working but very intermittent. It signifies a short circuit due to an exposed wire or faulty wiring.
Malfunctioning Electrical Device
The next reason is overloading the circuit. It roots from damage to the inside of the windscreen or light system motor, car AC, etc.
These failures cause the electrical capacity to rise higher than normal, eventually causing an overload of the current flow.
Wet Conductor
Wet conductors can also cause an immediate short circuit. If you find exposed wires or leaks in some electrical components, the fuse wires may have been wet, causing a short circuit.
Use Unmatching Amperage Fuse
Another cause of a blown car fuse is improper fuse replacement. When you use a new fuse with a higher amperage than the common amperage allowed, the fuse will blow.
In addition, if the fuse is installed in the wrong place, it will also lead to a short circuit, resulting in the inoperability of the vehicle systems due to a faulty fuse.
How To Replace a Car Fuse?
Step 1: After locating the fuse box, open the fuse box, have a visual inspection, and find the burned fuse.
Burned fuses are usually black, or you can rely on the fuse diagram printed on the inside of the fuse cap or provided in the vehicle owner’s manual.
Step 2: Use clamps, plastic tweezers, or small pliers to remove the damaged fuse from the control panel.
Step 3: Check the maximum amperage written below or next to the failed fuse. You can rely on the color of the burned fuse to know its amperage and buy the exact fuse you need.
Refer to the table of the amperage rating below:
| Black | 1A |
| Grey | 2A |
| Violet | 3A |
| Pink | 4A |
| Tan | 5A |
| Brown | 7.5A |
| Red | 10A |
| Blue | 15A |
| Yellow | 20A |
| Clear | 25A |
| Green | 30A |
| Orange | 40A |
| Red | 50A |
| Blue | 60A |
| Tan | 70A |
| Clear | 80A |
Step 4: Buy a fuse with the same power supply, and push the new fuse into the slot in the box. Finally, put the fuse panel back in its original position.
You can see how to change the fuse in your vehicle’s owner’s manual or have a mechanic fix it if there are more serious problems with your car.
FAQs
How Much Does It Cost To Replace A Blown Fuse?
Replacing the fuse is pretty simple as the car fuses are not complicated systems. Thus, many experts in electricity say that you can replace the fuse yourself and only spend about $10 to buy a new fuse.
It will be best to buy multiple fuses at a time to reserve for sudden failures.
However, should you decide to go to the auto repair shop to have the repairers replace it, they may charge an additional labor cost (about $65 to $100 per hour).
So you should call the dealer or car repair shop in advance to know the exact price.
It usually takes a mechanic 15 to 20 minutes to change a fuse so it will cost you about $50 to $100 in both labor and new fuse costs.
In addition, if the problem is still not resolved after replacing the fuse, you should have the professional technician check it further because other parts may also be damaged.
How To Prevent A Fuse From Blowing?
One of the things you can do to avoid blown fuses is to check your electrical system regularly to spot problems and fix them early, avoiding more serious damage.
Also, don’t let the lights, heating, or air conditioner operate at full capacity, as even a small leak can cause a short circuit and blow a fuse.
You can purchase a soft starter to reduce the peak capacity of the electrical systems in the vehicle.
You should not expose components in the engine compartment to water because the electrical wires can become exposed and get wet, causing a short circuit.
Check power lines regularly to replace worn or outdated wires.
Clean your vehicle regularly to prevent dirt and steam from accumulating, shorting the car’s components that may cause a burned and damaged fuse.
Conclusion
What are blown fuse in car symptoms? If the whole car’s electrical system is not working, or some electrical systems in the vehicle are not working properly, it’s a blown fuse.
Additionally, black streaks inside the fuse are common signs of a blown fuse. Once the test light is not bright when detecting the fuse, then the fuse has burned out completely and needs to be replaced.
We hope you know how to replace the fuse and fix the problem easily. See you in the next post!