Wire harness assembly plays a crucial role in numerous electronic devices, including automobiles, tablets, flight simulators, and more. However, it is a complex and time-consuming process that demands manufacturers to invest significant effort. Despite the challenges, the demand for wire harness and cable assemblies continues to surge, driving the expansion of manufacturing scales. In this article, FS Technology will provide a step-by-step guide to wire harness assembly, helping you gain a clearer understanding of how this process unfolds.

Step 1: Design

Whether concealed behind a vehicle’s dashboard or integrated into the internal workings of household appliances, wire harnesses effectively facilitate the transmission of power and information. Engineers involved in electronic product development must overcome various challenges through meticulous design and planning to ensure the functionality of wire harnesses.

During the initial design phase, engineers must make critical decisions regarding the selection of wire harness components and establish specific usage specifications. Careful choices of wires, connectors, terminals, and protective elements are essential, tailoring each component to meet the electrical requirements and environmental conditions of the product. Factors such as wire gauge, insulation materials, and connector types must align perfectly with the operational needs of the equipment to ensure optimal performance and reliability.

Drawing a meticulous wire harness blueprint based on the unique electrical requirements and functions of the product is crucial for the success of the project during the design phase. The entire process requires attention to detail, as engineers navigate through the maze-like specifications and considerations. Additionally, a comprehensive assessment of the electrical system ensures seamless integration between the wire harness design and the expected functionality of the equipment.

Beyond technical considerations, the wire harness design phase also requires strategic planning and foresight. Engineers must contemplate the scalability of production, anticipate future demand fluctuations, and potential design modifications. This proactive approach ensures adaptability and cost-effectiveness in the manufacturing process, allowing for seamless transitions and adjustments as needed.

Step 2: Prototyping

This pivotal stage allows engineers and product designers to tangibly interact with a physical rendition of their eventual product. By creating a prototype of the wire harness, they gain the opportunity to rigorously test its functionality within its designated application.

This preliminary examination is vital before initiating the initial production phase, guaranteeing that the harness operates at its peak performance level. The hands-on experience of evaluating the prototype provides valuable insights and allows for necessary refinements, ensuring that the final product meets or exceeds the desired specifications and functions seamlessly within its intended environment.

Step 3: Production & Assembly

a. Assembly Challenges

Unlike other sectors of electronic manufacturing, the wire harness assembly process still heavily relies on manual assembly. While some companies providing wire harness assembly services have integrated automation into their facilities, the need for high customization based on each application ultimately requires manual intervention. This poses challenges to the precision and task-oriented nature of wire harness construction.

From a geometric perspective, wire harnesses are meticulously designed to snugly fit specific spaces within a larger electrical grid or run parallel to other components. Additionally, their tasks include grounding and protecting wires from potential internal and external threats, ranging from crossed wires to exposure to chemicals or moisture.

In the wire harness manufacturing field, adhering to design specifications and maintaining high-quality standards is crucial to minimizing errors.

b.Stripping and Connections

The first step in creating a wire harness involves precise wire cutting, accomplished by specialized wire-cutting machines to ensure the correct lengths.

Subsequently, the wire ends are stripped to expose the cores. This prepares them for the attachment of terminals, connector housings, or modules.

Next, the wires are assembled into a harness using workbenches or assembly boards to meet specific design requirements.

c.Manual & Automatic


Manual-manufacturing wire harnesses involve manually routing wires through sleeves and applying fabric tape as necessary, particularly on branch outs from wire strands. Crimping terminals onto wires and multiple crimps for attaching more than one wire to a single terminal are essential manual tasks. Additionally, inserting sleeves into each other, securing strands with tape, clamps, or cable ties are done by hand.


Integrates automation and machinery. Cutting machines ensure uniform wire lengths, while machines are utilized for crimping terminals or partially inserting wires with fitted terminals into connector modules. Soldering machines are used for sealing wire ends, and tools assist in twisting wires as needed.

Step 4: Electrical Safety Testing

The creation of wire harnesses is a systematic process that requires meticulous planning and a significant amount of manual craftsmanship, from conceptualization, design, and assembly to the transition from the drawing board to the completed harness.

Once the manufacturing process is complete, a crucial phase follows: testing. These tests are not merely obligatory checkpoints; they serve as vanguards of reliability, ensuring the seamless integration of these harnesses into the operating system.

We mandate rigorous electrical safety testing for each harness. These assessments thoroughly examine various aspects, including the electrical integrity of the harness, its flexibility under different conditions, and compliance with specified specifications. Ultimately, they ensure that every harness is 100% reliable and capable of uninterrupted operation.

Shenzhen Thriver Digital Tech Co., Ltd.  provides customers with 10 years of leadership and experience in advanced PCB and PCBA Assembly technology, with proven processes and a full range of services.