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HomeTips & GuidesWiring Harness Assembly: The Ultimate Guide

Wiring Harness Assembly: The Ultimate Guide

The connection of a machine’s or vehicle’s electrical components is an essential part of maintaining its electrical safety and health. A wiring harness assembly helps ensure all the electrical systems are properly and securely connected. 

Read the article below to learn all about wiring harness assemblies and their various applications and benefits.

What is a Wiring Harness Assembly?

A wiring harness assembly is a joined collection of connectors, wires, and cables to facilitate the transmission of electrical power and signals between different components of machines.

Basically, an assembly is customized for a certain purpose, and its complexity varies according to the number of connectors and wires required. 

Also, a wiring harness assembly must adhere to rigorous durability, safety, and performance standards during design and manufacturing. 

Wire Harness Assembly vs Cable Assembly

Often, people confuse a wire harness assembly for a cable assembly; however, the two are different. 

The key difference is that a wire harness assembly features various breakouts (ends) running in different directions with a number of terminations on every breakout, while a cable assembly only features two ends. 

Wiring Harness Parts

Below are the key components of a wire harness assembly.

  • Connectors – these are used to join two wires together. Common connectors are female and male connectors that join vehicle wires from one side to another. You can do this in a number of ways, such as soldering and crimping. Connectors are available in various sizes according to the type of vehicle you own however, there are some main common features. While some connectors require assembly, others are pre-assembled.
  • Terminals – these are used to connect wires to circuit boards or other devices that require a connection. Often, they’re referred to as plugs or jacks.
  • Wires – these convey electricity through your vehicle and connect different components via terminals and connectors.
  • Locks – they help prevent short circuits and accidental disconnections by keeping connections closed.



Where are Wiring Harness Assemblies Used?

Since wiring harnesses are capable of solving a number of interconnection challenges, they’re used extensively throughout a variety of industries.

  • Automotive-wiring harnesses are important for saving space within vehicles in lighting/signals, under the hood, in the dashboard, and various other areas.
  • Aerospace-wiring harness assemblies are often used in various aerospace components like drones, aircraft, and satellites to facilitate communication, power transmission and much more.
  • Telecommunications – a wiring harness helps utilize space usage in a wide range of telecommunication equipment like repeaters, modems, routers and various other broadband and communication equipment.
  • Medical – clinics and hospitals depend on wiring harnesses to protect and organize wires in equipment such as dental equipment, imaging and diagnostic equipment, crash carts, and various other equipment.
  • IT – almost every server, laptop, computer, and other various IT technology has a wire harness to optimize space for easy installation and identification by technicians.
  • Robotics and Automation – wiring harnesses are used on robotics and almost every automated machine to route, group, and protect wires.
  • Manufacturing CNC and other manufacturing equipment depend on harnesses to organize and route internal and external wiring.
  • Construction-wiring harnesses are commonly used within structures to facilitate wiring installation and organization.

Benefits of Using a Wiring Harness Assembly

Often, wiring harness assemblies are incorporated into various electrical systems in order to improve efficiency by the following.

Saves Valuable Space

A major benefit of using a wire harness assembly is that it organizes your wire and cable arrangement. 

By properly and in an orderly manner clustering wires and cables in a single external casing, a wire harness assembly decreases the space required to house your wire setup.

Protects Wires and Cables

Wire harness assemblies not only organize wires and cables but also protect the durability and functionality of wires and cables.

 Intersecting and interconnecting wire and cable setups could reduce performance and damage the wires and cables. 

Organizing your wires and cables using a wire harness assembly helps minimize decreased functionality and helps prevent damage from external forces. 

Furthermore, the thermoset casing or outer thermoplastic of the harness serves as a buffer against negative impacts associated with lacerations, accidental vibrations, and moisture.

Also, a wire harness assembly can help protect your wires and cables against electrical damage. 

An insulating sheath covers the bound wires and cables to prevent electrical damage. 

Additionally, the chances of an electrical short are reduced because the sheat grouping of the wires and cables is tightly bound. 

Wiring Harness Assembly Design

In their most basic form, wire harness assemblies could contain only a few wires or cables with only the necessary terminals installed.

On the other hand, in electrical systems that need various functions and operations, the wire harness assembly could contain countless wires and cables that, if not for the assembly, would represent a never-ending labyrinth. 

To sum it up, the functions of the electrical system will decide how complex the wire harness assembly is.

A wire harness process is designed according to the electrical and geometric requirements of the component you plan on the harness onto. 

Once you establish the initial design you will need a schematic to create the manufacturing paperwork and assembly board of your harness. 

An assembly board is a full-size illustration of the harness detailing all the components and their positions. Also, it serves as a workbench for your harness. 

Other factors that Bear on Harness Design Include

  1. Whether you plan to expose your harness to continuous flexing.
  2. If you’ll use your harness outdoors, indoors, or under certain conditions.
  3. The number of conductors and circuits your assembly needs and their characteristics.
  4. The voltage level to be conveyed.
  5. Any potential exposures include chemicals, extreme weather conditions, moisture, and corrosive fluids.
  6. Average, maximum, and minimum operating temperatures and potential fluctuations.
  7. Local environmental and safety regulations that could impact component installation, selection, and inspection.
  8. Breakouts, routing, and general shape or form.

What is the Standard For Wiring Harness Assembly

The IPC/WHMA-A-620 serves as the industry standard for wire harness assembly. 

The ITU developed the standard to ensure products are manufactured and tested according to a set of standards, and this includes performance requirements and wiring diagrams.

It also defines how you should wire electronic equipment to ensure proper functioning and simple repair. 

Furthermore, it defines how you should design connectors to enable easy attachment to cables or wires already in place on the circuit board of an electrical device.

Wiring Harness Assembly/Manufacturing Process

It’s essential to properly wire up and connect a wiring harness because if you’re not careful, it could cause problems. Below are the steps you need to follow.

  1. First, using a wire stripper or wire cutter, cut your wire at the right length. You should cut your wire to fit snugly into your connector housing on either side.
  2. Then, crimp center connectors onto every side of your wiring harness. The connectors normally have an inbuilt crimping tool to ensure they are tightly crimped onto both sides of the harness. This makes it easier to connect when you want to connect it to something else, such as an oxygen sensor, brake sensor, or electric motor.
  3. Next, connect one end of your wiring harness to each side of the connector housing using an electric connector.
  4. Lastly, test your wiring harness for electrical functionality. For this step, you’ll need the assistance of a pre-programmed test board. The test board is programmed with the required electrical characteristics, and all you have to do is plug in your harness to check for any faults.

Why is Wire Harness Assembly Done Manually

Assembling a wiring harness is one of the few manufacturing processes done more efficiently manually than via automation. 

Due to the different processes involved in assembly. The manual processes include;

  • Conducting multiple crimps
  • Installing terminated wires in different lengths
  • Taping breakouts
  • Binding the parts with clamps, cable ties, or tape
  • Routing cables and wires through conduits and sleeves
Cables Bound With Cable Ties

Cables Bound With Cable Ties

Due to the difficulty that comes with automating such processes, manual assembly continues to be cheaper, especially for small order sizes. 

Also, why does the process take longer than other cable assembly types? 

Production time could range from anywhere between a couple of days to a number of weeks. 

A more complex design will take longer to produce.

However, some phases of pre-production benefit from automation, such as;

  • Crimping terminals on a single or both sides of a wire 
  • Automating the process of cutting and stripping the ends of wires
  • Twisting wires
  • Soldering wire ends

Looking Forward to a Wiring Harness Assembly Manufacturer

If you’re looking for a custom wiring harness, Cloom has your back. 

Our team of highly skilled professionals is committed to creating customizable, high-quality wire harness assemblies for original equipment manufacturers.

Our automated wire capabilities include;

  • Stripping
  • Cutting
  • Terminating
  • Soldering
  • Splicing

We can handle wires and cables ranging from 4/0 AWG to 24 AWG. Cloom is ready to work on all order sizes that cover various applications such as;

  • Hardware
  • Consumer goods
  • Telecommunications
  • Electronic
  • Industrial machinery
  • Gaming and amusement
  • Transformers

Furthermore, you can choose from various cable types, style options, and materials, such as;

  • Lacing
  • Wire ties
  • Custom colors
  • Any type of insulation material
  • Heat shrink coatings
  • Custom shielding
  • Individual tagging
  • Custom barcoding and labeling
  • Independent circuit IDs
  • 4-color ink stamping
  • Paper, polypropylene, and nylon fillers
Heat Shrinking Tubing

Heat Shrinking Tubing


At Cloom, we take all the necessary measures to ensure you get a wire harness assembly that best serves your needs. 

Our team of skilled professionals takes into account all the necessary regulatory standards to ensure your design is reliable, safe, effective and compliant. 

Feel free to contact Cloom Tech for all your custom wiring harness needs.

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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