HomeTips & GuidesAutomotive Fuse Panels: How Do They Work With Your Auto Wiring Harness

Automotive Fuse Panels: How Do They Work With Your Auto Wiring Harness

Automotive fuse panels are essential for any vehicle as they protect electrical accessories from sudden failure. Because of the fuse in the fuse box, many electrical components such as dashcams, rear cameras, or radios are working great.

Most of the problems that occur in your vehicle are only associated with the fuses. So, you must know the physical and functional aspects of an automotive fuse box or panel.

The article details everything about auto fuse panels.

Understanding automotive fuse panels:

As an electrical system part, a fuse panel divides the incoming source current into different circuits, where one fuse protects each circuit from the overcurrent. 

Based on the application, you can also call a fuse panel, a fuse box or a fuse block. 

It is part of different electrical systems, including an auto fuse panel found in various vehicles.

These automotive fuse panels control the electricity supply in trucks, cars, and buses.

 It’s like a power system for the whole electrical system; thus, you can check resistance, voltage, or current continuity at this access point.

Earlier, vehicles used to have fuses and relays at random positions. However, later on, introducing a fuse panel to accommodate all fuses and relays in one place improved the functioning and maintenance.

 In the fuse panel or fuse box, all the fuses and relays are present and come with proper labeling, allowing easy identification. 

Vehicles may also have one or more fuse panels (smaller than the power center) in the interiors. 

These panels accommodate fuses for low amp electrical components such as power seats, power outlets, windows, radios, cabin lights, horns, etc. 

Other than these, fuses for high amp circuits are present on the power center or the main fuse panel.

Old car engine fuse panel

Old car engine fuse panel

How do automotive fuse panels work?

An automotive fuse box has relays, fuses, and diodes to protect circuits from current overloading. Here, we explain the role of each component in the fuse box.


A fuse mainly protects the wiring, available in different sizes. You can place them in any circuit for their protection. 

For example, a fuse connected to a radio circuit will protect your radio when there is more current flow by blowing itself. 

As the fuse blows, you only need to replace the fuse rather than the radio and the radio wire.

Each fuse comes with a particular ampere limit; further, all the fuses come in different colors for easy identification. 

You must use the right amperage fuse to ensure complete safety.


A relay is like an electric trigger that activates itself with a small amount of current but activates another component with a high current value.

A relay has a coil of wire that works as a temporary electromagnet with current and activates the relay.

Fuses in different colors

Fuses in different colors

Problems with automotive fuse panels:

Fuses in the fuse box protect electrical accessories, while relays protect the passengers from the sudden high current from the battery and the alternator. 

The fuse box protects the relays and fuses from various weather conditions. However, they may overheat and fail for several reasons.

Blown fuse:

Whenever a high current flows, the fuse overheats melts, and disturbs the electricity flow.

Apart from this, sometimes the fuse also blows due to age, overuse, or overload of accessories. 

Ensure that you always use the correct amp fuse for a particular circuit. A less amperage fuse will blow at low currents, while a high amperage fuse will not blow even when high current flows. 

Using a high amperage fuse in a low amp circuit area can cause damage to the electrical component.

When the problem is a blown fuse, you can rectify the problem by replacing the fuse. Here are the steps for fuse replacement.

  • Switch off the ignition and the circuit that has a blown fuse.
  • If the fuse is a spade-style or mini fuse, it will come out of the socket when blown. You can use a plier or a puller tool to remove it. However, if it is a bolt-in maxi fuse, grab a screwdriver or a nut driver to remove it from the power center.
  • Once removed, push the new fuse in place to restore the current flow in the circuit.
  • Turn on the ignition after the fuse installation. Turn on the device for which you replaced the fuse to check if the circuit is working fine. If the problem persists, there is some kind of short circuit that you need to find and repair.

Electrical relay failure:

Sometimes, when your car does not start, and the fuse box clicks, the problem is probably with the relay. 

The problem in the relay arises due to some fault in the vehicle’s computer, power supply disruptions in the relay area, or some faults at the ground wire towards the relay side. 

If you fail to identify the exact reason for your problem, you must call a technician.

Further, relays carrying high loads and constantly getting switched ON/OFF have higher chances of failure.

On failure, a relay stops the power flow to the device. For example, a failed relay in the fuel pump will prevent the engine from starting as there is no fuel pressure. 

If an air conditioner clutch relay stops working, the compressor won’t work, and you will not feel cold air from your vehicle’s A/C. 

Most Chrysler vehicles require a cooling fan relay to allow power flow to the A/C compressor. 

In such cases, if the cooling fan relay fails, it prevents the compressor clutch and the fan from working.

You can replace a relay with the correct one on its failure. 

Sometimes, two relays look alike, but they may be connected to different components and are designed to handle other current loads. 

So, always be careful to use the correct replacement relay.

Look for the OEM part number of the relay and the vehicle application’s make, model, and year. 

While removing or replacing a relay, always cut the power off; otherwise, you can damage other electrical components. 

Also, apply some dielectric grease around relay terminals to avoid corrosion while replacing.

Fuse panel on battery box

Fuse panel on battery box

Custom 12-Volt automotive fuse panels wiring harness:

You must learn how to wire an auto fuse box when you want to add a new electrical component. For plug-and-play installations, you need a custom relay box wiring harness

Consider the following factors while you design the relay box wiring harness for your vehicle.

  • First, look for the number of relays and fuses you want in the relay box.
  • Identify all the electrical components you want to connect with relays and fuses.
  • Consider the mounting option and dimensions of the relay box so that it fits well into your car’s electrical setup.
  • Check if the relays and fuses are compatible with your car’s electrical components.
  • Choose pre-wired relay sockets or not.

Our custom-designed relay boxes are not only functional but cost-effective, too.

  • You can find a comprehensive range of relay boxes from trustworthy brands like Painless Performance, American Autowire, or Eddie Motorsports. 
  • You can find standard relay options or different configurations to accommodate a variety of applications, from single relay blocks and multi-relay panels, to individual relays.
  • Whether you install a new pump, light, or fan, with our diverse relay box options, you can find the perfect one for your car’s electrical system. 
  • You can use our automotive relay boxes for switching different functions, whether it’s the advanced safety feature or modern comfort accessories.
Fuse box wiring harness

Fuse box wiring harness


An automobile wiring harness is a complex and delicate part of the vehicle’s electrical system. Even a small error may be harmful to you and your car’s accessories. 

For any help regarding the auto fuse box wiring harness, contact Cloom. We have a comprehensive range of these products to suit customers’ specific requirements. 

Hi I am Christa, sales manager of Cloom.

I have extensive expertise and experience in wiring harnesses and I believe I can help you.

And we have a very professional technical team who can clearly understand the customer’s needs and give professional suggestions and solutions after receiving the drawings.

If you also have wiring harness needs, please send me the drawing so that we can give you our quote and start our business.

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