Tips Sahabat

What is a Relay in a Car? Here are Its Functions & How It Works

09 April 2025
fungsi relay pada mobil, jenis dan cara kerjanya

Understanding the various components in a car is a duty for all car owners, especially crucial components like relays in cars. By knowing these components, you will understand the function of the relay in a car and how it works.

Curious, right? Let's dive into a complete review of what a car relay is, its functions, and how it works:

What is a Relay in a Car?

A relay is an electrical component in a car that consists of a point (electromagnetic) and a coil part. Essentially, this component functions as a controller of the electric flow and channels electricity. That is why your car needs to use a relay.

Functions of a Relay in a Car

What is the function of a relay in a car? Besides being a controller of electric flow, relays in cars have several functions as follows:

1. Can Extend the Life of the Switch

The function of a relay is to extend the life of the switch. For the relay to work optimally, this component requires a sufficiently large electric current.

This current will then be channeled to electromagnetic components such as car lights, AC compressors, and others through the switch.

The switch itself functions as a generator of electric flow. The installation of a relay in a car can prevent the switch from melting due to heat, making it more durable.

2. Reduces Resistance in the Current

The second function is to reduce resistance in the current. The presence of resistance in the electric current in a car can affect the performance of several electromagnetic components, such as a faint horn and dim car lights.

With this relay, the resistance can be reduced so that the electric current can flow maximally to the car lights, horn, and other electromagnetic components.

3. Locks the Car

The next function of a relay in a car is to lock the electromagnetic activity (automatic electric current security or connection and disconnection of electric current) in the car.

Read Also: Must Be Repaired Immediately, Recognize the Signs of a Damaged Car Starter Relay

4. Acts as an Electromagnetic Switch

The coil in the relay that has been energized can generate a magnetic force that functions to pull the point part so that terminals 87 and 30 are connected.

5. Makes the Horn Louder and Car Lights Brighter

The use of a relay in a car will increase the electric current in the car so that the car lights are brighter when turned on, and the horn is louder.

6. Avoids Wear and Damage to Other Components

The large electric current channeled by the relay can make the performance of the car's electrical components work optimally so that car components do not wear out and get damaged easily.

How a Relay Works in a Car

Not only the function of the relay that you must understand, but also how the relay works. Essentially, a relay has several terminal parts, namely terminal 30, 85, 86, and terminal 87.

The electric current in the relay coil comes from the electric flow passing through terminals 85 and 86. Then it generates magnetic power used to pull the contractor part. This magnetic power is then channeled from terminal 30 to terminal 87.

This performance will repeat continuously, thereby reducing the resistance of the electric current and making the electromagnetic components less prone to wear and damage.

Types of Relays in Cars

The many benefits obtained from relays make you need to try using this component in your car.

However, you need to know that not all relays can be installed in cars. You must be able to choose the right relay. Here are some types of relays you need to know.

1. 3-Pin Relay

This type has three terminals, namely 30 (this terminal is connected to terminal 85), 86, and 87.

2. 4-Pin Relay

This type functions as a switch controller for terminal 85. Usually, this component serves as the basis for an electrical circuit with a single load on the horn and fog lamp components.

Read Also: How to Install Additional Foglamp Relay in Cars

3. 5-Pin Relay

This type of relay functions as a controller of electric current to the stop lamp or headlamp, and prevents electric current resistance. Usually, this type of relay has an additional terminal, namely 87a.

4. 8-Pin Relay

This type of relay can provide two instructions simultaneously on one switch to execute electrical instructions. Considering the different needs of each car, this type of relay is rarely used.

That is the discussion about the function of relays in cars, including their types and how they work. To ensure the relay can be used optimally and safely, it is advisable to consult installation by visiting the nearest Daihatsu dealer or authorized workshop.

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