Automotive Wire Harness Connectors: An ultimate guide on wiring connectors for automotive applications

Today, features like Light sensors, Powerful stereo systems, Internet access, advanced driver assistance systems, and voice control systems are common in every vehicle, which means the ever-increasing diversity of the connection systems. According to SourceToday, there were 240 connectors in an average vehicle five years ago. We will understand automotive wire harness connectors in detail.

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Automotive Wire Harness Connector Basics

The automotive wire harness is an assembly of the connectors, cables, and terminals spread throughout the vehicle. 

And connectors are responsible for transmitting electric power and information to different components within your car. There are different types and varieties of connectors used by automakers; for example, printed circuit boards, circular, rectangular, charging connectors, etc.

These connectors connect or disconnect the electrical lines and consist of male and female terminals. Male and Female terminals are collectively combined with linking you to the electrical connection, which results in fulfilling your desired action (e.g., automatic window or stereo system).

Wire harness in Motor Vehicle

Wire harness in Motor Vehicle

What are the main functions of the Automotive Wire Harness Connector?

These connectors fulfill three purposes.

Internal connectivity

These connectors connect the components inside the car. For example, stereo systems, sensors, etc. 

External connectivity

You can use the connectors during the car repair process. Mechanics try to detect the real situation of the car by connecting the vehicle with external equipment via an external connector.


You can also use the connectors to replace other connected devices. Although for a temporary period, these connectors play a crucial role. By then, you are free to use your vehicle.

Electric cabling in car

Electric cabling in car

Characteristics of Automotive Wire Harness Connector

It is no secret that automotive connection systems have high standards due to the different environmental factors involved in the vehicle’s functionality. And the OEMs (Original Equipment Manufacturers) keep the technical reliability sharp in light of the environmental conditions such as vibrations, braking oil, engine oil, high temperature, etc.

Here, it is super important that the different connections within the vehicles are connectable or disconnectable in rough working conditions. Therefore, producers focus on inventing a powerful connection system to ensure your car’s best performance.

Automotive-colored connectors

Automotive-colored connectors

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Automotive Wire Harness Connector components and their functionality

Consider the following different components to make things easier for your understanding of the connector.

Connector Housing

You can use the connector housing to carry the terminals and pins while securing the connection with the mating part. You can also call it plastic insulation, whereas its design differentiates between male, female, sealed, and unsealed connectors.

However, it is crucial to know that the sealed connection system contains a radial seal that guards your electrical system against dust and water. Furthermore, this component has different coding in various notches. Also, manufacturers mark it with various colors to help new people understand its works.

Terminal Position Assurance

As the name implies, you will mobilize the terminal positions together in the housing through your hands. You insert the crimps into the housing and create a technical link. For assurance, the automaker/mechanic hears a sound of a certain click.

Electricians introduced this clicking property of the terminal to reduce mistakes in mass production. Once you make the perfect technical link, you will set the secondary lock to keep the connector in its location.

Connector Position Assurance

All the connectors are assembled connection systems via hands. Of course, if connectors lack proper assembly, you may be able to achieve the electrical connection. However, the connector will not protect the connection against water and wind.

Single Wire Seal

Most people use it to protect the cavity against environmental conditions. Automakers ensure to crimp the seals into the terminal and cable in one step and push it into each cavity. These Single wire seals comprise an important fluid known as silicon oil that supports the assembly process.

Block seals

Block seals also play a role similar to a single wire seal and protect the cavity from external factors while offering openings to retain cables. It means that a block seal guards several cavities altogether.

Cavity Plug

A cavity plug protects unused cavities from external environmental factors by blocking them. You can insert and remove them using your hands or a screwdriver.

Wire harness with plastic housing

Wire harness with plastic housing

Types of Automotive Wire Harness Connectors based on connection systems

You can connect three types of connection systems as per desire.

Wire-to-wire Connection 

This type of connection comprises male and female connectors. Mostly, it connects and disconnects small applications and creates a link with the main wire harness.

Board-to-wire connection

The connection is fixed to a conductor board using this type of connection system. Here, the conductor board is linked to the male connector known as the “PCB Header.” On the other hand, the female terminal links to the wiring harness. This connection connects the engine control unit with the main power source.

Device Connections

This type of connection system is used mainly in sensor systems. And similar to the board-to-wire connection, it is composed of female mating parts already assembled for the given application.

Cable assemblies

Cable assemblies

Types of Automotive Wire Harness Connectors based on the electrical system

According to ISO standard 10487, there are about four types of connectors.

A-Group connectors

These connectors, also known as Power Connectors, join the vehicle’s head unit to the power supply unit.

B-Group connectors

These types of connectors are used to connect the speaker around the vehicle.

C-Group connectors

These types of connectors are optional and used to connect peripherals.

D-Group connectors

These types of connectors are optional similar to C-Group and are used to connect the navigation system.

Wiring harnesses under the dashboard

Wiring harnesses under the dashboard

Standards of the automotive connectors

Automotive electrical connections are prepared, tested, and installed in the vehicles per global standards and specifications. It includes ISO:

10487 for passenger car radio connections.

7736 for Road vehicle front radio installation.

 9458 for Passenger car motor connections.

Challenges faced in the automotive connector industry

With technological advancements in heavy-duty vehicles, many connectors are used to overcome excessive stress and strain experience. However, manufacturers tend to rely heavily on connector equivalents or component availability. Therefore, it creates multiple problems since this connector equivalent is less durable than the real connectors.

Another challenge faced in the automotive connection industry is sourcing wire harnesses in today’s market. Several distributors either do not deliver the connectors and wire harnesses on time or don’t have the desired quantity.

Wiring harnesses

Wiring harnesses


There is a rising need for more durable wiring and connectors as modern automobiles become increasingly networked and microprocessor-controlled. Do you need help with them? Here at Cloom, we offer wiring harness and cable assembly solutions so that you do not have to worry about perfection.

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