HomeTips & GuidesHow to Find out What Wire Harness you Need for Your Car

How to Find out What Wire Harness you Need for Your Car

Different wiring harnesses are required for vehicles such as vintage cars, project cars or off-road vehicles. However, how to find out what wire harness you need for your car? To get an answer to this question, you first need to get answers to the following questions.

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How many circuits do you need in a vehicle?

Any automotive wiring harness has wires and components that connect electrical devices to the vehicle’s main power source. 

Generally, wiring harnesses come with a fuse block along with 8-12 circuits at minimum. 

The circuit is mainly a wire designed for a specific use. For instance, headlights have two circuits for two headlamps comprising wires. 

On the other hand, a glove box bulb has only one circuit having a single wire. 

Your vehicle’s total electric components decide the quantity of circuits required. For example, a simple vehicle like an off-road car may need fewer circuits.

 However,  a large one, like a classic car with expensive components, may need more circuits. 

Depending on the circuit requirement, you may find 12,18, and 24-circuit harnesses in the market. However, the main difference among these is that of vehicle compatibility. 

Engine wiring harness

Engine wiring harness

How much does wiring harness quality matter to you?

All wiring harnesses comprise wires and many connectors, so how can you decide about the quality of the harness? 

Check the connection of connectors:

For connectors with only crimped connections,  there is a chance that they have not included all the wire strands. 

If a crimped connection takes only half of the wires, it will conduct less electricity. If there is less conductivity, it means there is high resistance, resulting in voltage loss.

 As a result, many of your components will not operate in low voltage conditions, leading to premature wear out. 

There is no conductivity issue when crimping and soldering, even if it leaves some wire strands. 

Further, the combination of crimping and soldering results in rugged connections. 

These connections are preferred on racing vehicles and off-road buggies. 

Thus, these crimped and soldered connections are the standard when designing good automotive wiring harnesses. 

Check if you can expand the harness:

Before picking any wiring harness, it is advisable to decide on the electrical accessories that you wish to install in your car. 

These accessories include headlamps, phone chargers, brake lights, music systems, trunk bulbs, etc.

If you know about electrical accessories, you can decide how many circuits you need and what amperage is needed to feed them. 

Further, if you also plan to install more accessories in the near future, it is good if you buy a wiring harness with extra circuits.

 This is important so you can easily expand the installed harness without buying a new one. 

Always look for an expandable harness, which is important even if you do not wish to expand the number of circuits. Why so?

When the harness comes with an expandable feature, it comes with more amperage capacity than the circuits it already carries. 

Further, a harness has to use heavy gauge wiring to accommodate more amperage. 

This oversized wiring ensures a minimum voltage drop in the current path in each circuit. 

Also, it ensures that the harness performs well in all weather conditions. 

Check if the wiring harness is easy to install

You can design automotive wiring harnesses in three ways. They are:

  • When the wires in the automotive wiring harnesses are connected to the fuse panel, you can route these wires to the terminating point, cut them to the required length and connect them to the load.
  • In some other harnesses, wires start from loads. Again, these harnesses cut the wires to the required length and connect them to the fuse panel. 
  • Lastly, factory wiring harnesses have a termination at both ends. You only need some additional plugs for easy installation.

All three types of automotive wiring harnesses come with some merits, but the best is to purchase a new one. In these, wires connect to the fuse panel, thus making routing and installation much easier.

Custom wiring harness


Installing a wiring harness is complex, so you must ask for an expert’s opinion, which becomes more important when dealing with a customized harness

Contact Cloom if you have further questions, as we manufacture superior-quality wiring harnesses and cable assemblies used in various applications.

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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