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HomeTips & GuidesCar Wire Harness Labels: Types and Importance of These Tags

Car Wire Harness Labels: Types and Importance of These Tags

We’ll look at the types, importance, and information you can include in car wire harness labels to make them effective.

Electrical wires usually have a color-coding format that enables you to identify the function of the cable.

 However, this format might be inadequate for complex wiring systems.

Therefore, you need an additional identification system, and car wire harness labels are your best bet.

Table of Contents

What Are Wire Harness Labels?

Wire harness labels are identification tags or markers placed on electrical cables to indicate the function or other vital information relating to the wire.

This labeled data helps installers, technicians, or electricians identify the wires for better organization and faster troubleshooting.

Types of Cable Wire Harness Labels Based on Design

These wire labels can have either of the following designs.

Heat-Shrink Labels

These heat-shrink tubing markers have a slide-on mechanism, meaning you insert them over wire insulations. Once in place, you must use heat (usually from a heat gun) to secure them on that spot.

Heat shrink labels

Heat shrink labels

Such label markers are ideal for automotive and aerospace applications because they are resistant to most of the elements, meaning they are highly durable.

Self-Laminating Labels

Self-laminating labels feature a white printable area (a piece of paper) and a transparent laminating tail that wraps around the printable area.

So, this transparent piece of tape laminates the printed sheet of paper on the outer side for protection, with the wire insulation forming the inner laminate.

Cable Flag Labels

Adhesive flag-shaped labels have two advantages. They are easy to read and have a large surface area to print the data. You can even place a barcode on this space.

However, they have a thin neck (the section that wraps around the wire), making them less durable than the other types.

An electrician replacing a wall switch and installing new wire labels

An electrician replacing a wall switch and installing new wire labels

Plus, they usually adhere to themselves after wrapping around the wire instead of sticking to the cable insulation. 

Therefore, they can move along the insulation surface, resulting in faster wear.

Wrap-Around Labels

As the name suggests, these adhesive labels wrap around the cable insulation and come with pre-printed markers because you can’t place the data after sticking. 

Although firm, these tags have limited space for printing data.

Hook-and-Loop Labels

These labels don’t need adhesive to attach the printed material.

 The plastic-made pieces feature grips for undoing the hook, meaning you can hook and loop one piece several times.

Types Based on Purpose

We can also classify these labels depending on their purpose in these categories.

Cable Label

Instead of affixing to an entire wire harness, a cable label attaches to only one wire in a bundle. 

So, instead of indicating the function of the harness, this tag highlights the wire’s gauge, polarity, function, reference number, etc.

Individual cables marked with labels printed using a thermal printer

Individual cables marked with labels printed using a thermal printer

Connector Label

As the name suggests, connector labels indicate the function of connectors for specific wires. The data on the label can be the pin assignment, connector type, and pin function.

Termination Label

Terminations are wire endpoints on a harness. Therefore, their labels can include details like the connection destination and terminal block number.

Component Label

Although components like sensors, relays, and switches are not part of wire harnesses, we will include their labels because you can encounter them when wiring.

These labels indicate the functions of these components and their level or position in the wiring system.

Warning Labels

Warning labels are self-explanatory. They provide information about the required safety precautions, especially on high-voltage wires.

Maintenance/Service Labels

These labels indicate the information about the scheduled maintenance or recommended service intervals to keep the harnesses or systems in tip-top shape. 

Some can even list contact information should you need technical support.

Colorful UTP cables with labels resembling the flag type indicating the connected line arrangement

Colorful UTP cables with labels resembling the flag type indicating the connected line arrangement

Serial Number/Date Code Labels

You need to know the manufacturing dates and serial numbers for some harnesses to help simplify maintenance. 

Some of these labels also include place of origin and product versions.

What Information Do Wire Harness Labels Give?

Wire harness labels can provide a lot of information, but it is usually in the form of these four formats.

Text and Integers

The most straightforward way of including data on labels is to include it as text and integers. 

Usually, the harness labels have information printed on the surface before sticking. 

But you can stick it after if dealing with some label variants, such as the self-laminating type.

Text and integer labeling on a terminal in a control panel

Text and integer labeling on a terminal in a control panel


Images can substitute or be used together with text to indicate the functions of individual wires or bundles.


Barcodes have various configurations to indicate information about harness bundles or individual wires. Some of these configurations include:

  • QR codes
  • Code 128
  • ITF-14
  • Code 39
  • EAN-13
  • Codabar
  • EAN-8

Certification Badge

The last format is the certification badge or code. It is usually from a standardization organization, such as UL, ISO, and IPC.

Importance of Cable Wire Harness Labels

Wire harness labeling is crucial for these reasons.

Color Coding Gives Little Information

Electrical wires feature color-coded insulations, but these colors can be overwhelming when dealing with complex harness bundles. 

Also, they usually indicate the function of the wire and its polarity.

This information might not give the required details. And it can be confusing if different companies have varying color-code formats.

Color-coded live, neutral, and earth wires with label markings

Color-coded live, neutral, and earth wires with label markings

For instance, the wire color codes for stock car radios can have different functions compared to the cables on aftermarket head units.

Therefore, it is best to have labels that indicate the wire functions in text, integer, or image format. 

Images and symbols are easier to understand than text because they break the language barrier.

To Ensure Safety

Although color codes indicate wire polarity, the code format can differ depending on the country or region. 

For instance, the positive wire in European countries usually has brown insulation, while the same wire in the American region is red.

A utility system control wiring with label markings for live, neutral, and other positive power supply lines

A utility system control wiring with label markings for live, neutral, and other positive power supply lines

To ensure safety when handling these wires, include labels with the polarity marking. 

Otherwise, someone doing a DIY project can cut a live wire and experience electrical shock or splice it to the wrong cable.

To Enhance Reliability

If replacing some parts of the wiring system, you might have to unplug some wires or connectors, and labels will ensure you get the correct ones.

Otherwise, you will disconnect the wrong wires, resulting in a shutdown of critical system parts or causing damage.

To Simplify Error Troubleshooting

When components or wires fail in an electrical system, car wiring, machines, etc., you need to know what each cable does to find the root cause of the problem.

Professionals might find the issue and repair it quickly due to experience. 

However, DIYers might have a challenge identifying the wire, connector, or terminal functions from a visual inspection.

Tags simplify wire and parts identification for quick troubleshooting and fixing.

Wrap Up

Car wire harness labels might seem unnecessary in cable bundles, but they help workaround some issues, especially when troubleshooting and fixing stuff. 

So, consider installing them, and you can use either of the types listed above.

We can help you source them for your project or even get you already labeled wire harnesses ready for use. 

Contact us or comment below for further details, and we’ll be in touch with the required details.

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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