Best Car Electrical System Relays of 2025
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Car electrical system relays are devices that help control the flow of electricity within a vehicle's electrical system. These small, but crucial components are responsible for activating various electrical components, such as headlights, power windows, and the fuel pump. Without relays, these components may not function properly or at all. Car electrical system relays are typically durable and long-lasting, but may need to be replaced over time due to wear and tear. It is important to choose high-quality relays to ensure proper function and safety while driving.
At a Glance: Our Top Picks
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#TOP 3
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Top 10 Car Electrical System Relays
Derale Electric Fan Dual Relay Wire Harness
This wire harness is designed for air conditioning fan relays and rated at a maximum of 25 amp continuous draw per each relay (total of 50 amps). It does not include fuses, but comes with an AC override circuit for each relay, providing convenience to users.
KC HiLiTES 3300 12V Relay
The KC HiLiTES 3300 12V Relay is a 5-pole, 40 Amp relay that is sealed for added moisture protection. It is easy to install and sold individually. This relay is a great addition to your car's electrical system.
Mopar Starter Relay for Vehicle
This Mopar 4727370AA Starter Relay is designed specifically for vehicles, with a fit type that ensures compatibility. The relay has package dimensions of 3.175 L x 12.065 H x 8.89 W (centimeters) and weighs 2.3 pounds, making it easy to install. The part number for this product is 4727370AA, and it falls under the category of car starter relays.
HELLA 007793041 Mini ISO Relay
The HELLA Mini ISO Relay is a universal relay designed for car electrical systems. With a rating of 12 Volts and 50 Amperes, this single pole, single throw relay is perfect for various applications. Whether you need to control lights, fans, or other electrical devices, this relay has got you covered. The included mounting bracket makes installation a breeze, ensuring a secure and stable connection. With the HELLA Mini ISO Relay, you can rely on its high-quality performance and durability. Upgrade your car's electrical system with this reliable and efficient relay.
HELLA 996152131 Time Delay Relay
The HELLA 996152131 12V Delay-On-Release, Time Delay Relay is an adjustable time delay relay that can be programmed up to 15 minutes with two dip switches and a control dial. This 4-pin relay is capable of 10 amp switching and carry for up to 30 minutes, making it a reliable and durable solution for your automotive control needs.
HELLA 007794021 SPDT Relay
The HELLA SPDT Relay is designed to handle up to 20 or 40 amps at 12 volts DC, making it ideal for various electrical applications. Its Form C configuration allows for versatile switching options, giving you flexibility in your projects. With an impressive operating temperature range of -40°C to +125°C, this relay is built to perform in extreme conditions, ensuring reliability no matter the environment. Additionally, it comes conveniently packaged with a dust cover, protecting it from debris and prolonging its lifespan, which means you can trust it to keep your systems running smoothly.
HELLA 933766111 MICRO Relay
The HELLA 933766111 MICRO Relay is a 12V, 20A Single Pole Double Throw/Form C relay with a Resistor Coil Suppression. It is designed for use in the electrical system of cars, providing a reliable and efficient method of switching power between different components.
Derale 16764 40/60 Amp Relay
The Derale Relay is a high-quality replacement relay designed for car electrical system relays. With a maximum continuous draw of 25 amps, this relay is capable of handling heavy electrical loads. It is the ideal choice for those who want to upgrade their relay harnesses (#16763 and #16765) for better performance. The compact size of this relay makes it easy to install in tight spaces. Additionally, the Derale Relay comes in a lightweight package, weighing only 0.1 pounds, which makes it convenient to carry and transport. Whether you are a car enthusiast or a professional mechanic, the Derale Relay is a reliable and efficient choice that will ensure the smooth operation of your car's electrical system.
HELLA 003510087 Mini Relay
The HELLA Mini Relay is a high-quality relay designed for automotive electrical systems. With over 100 years of experience in automotive lighting, HELLA ensures exceptional performance and reliability. This relay is conveniently packaged, making it easy for you to install and use. The durable construction means you can trust it to withstand the demands of your vehicle's electrical system. Whether you need to control lights or other electrical components, this relay offers the performance you need for a dependable setup.
Painless 30823 Headlight Relay
The Painless Headlight Relay is designed to enhance your vehicle's lighting system. With compact dimensions of 5.45 inches in length, 2.34 inches in height, and 4.15 inches in width, it fits easily into tight spaces. Weighing only 0.84 pounds, this relay is lightweight, making it simple to install without adding unnecessary bulk. Proudly made in the United States, you can trust its quality and craftsmanship. The part number 30823 ensures you have the right component for your car lighting needs, providing reliable performance and peace of mind on the road.
Frequently Asked Questions (FAQs)
1. What are the different types of car relays?
There are several types of car relays, including changeover relays, normally open relays, potted relays, flasher relays (such as thermal, electro-mechanical, LED, and wig-wag flashers), among others. Each type of relay serves a specific purpose in the car's electrical system.
2. What are the two major types of relays used in automotive electrical systems?
The two major types of relays used in automotive electrical systems are electromechanical relays and solid-state relays. Electromechanical relays are the most common type and are known for their characteristic clicking sound.
3. What is the most common automotive relay?
The most common automotive relays are make & break relays (Single Pole Single Throw - SPST) and changeover relays (Single Pole Double Throw - SPDT). These relays are widely used in automotive applications.
4. What are the most common signs and symptoms of a bad relay?
Some common signs of a bad relay include the vehicle not starting, the start relay remaining open after the engine is started, the starter making a clicking sound, and the vehicle starting intermittently. These symptoms indicate that the relay may need to be replaced.
5. What happens when a relay goes bad?
When a relay goes bad, it can cut off power to the fuel pump and ignition system, resulting in a no-power and no-start condition for the vehicle.
6. What car circuits need relays?
Relays are used in various car circuits, but a common example is the operation of vehicle headlights. A changeover relay can switch between circuits to activate the full beam or dipped beam as required. Another example is the car air-conditioning system.
7. What are the three main types of relays?
The three main types of relays are electromechanical relays, solid-state relays, and reed relays. Each type has its own characteristics and applications.
8. How many relays does a car have?
A typical car can contain up to twenty automotive relays, and they can be located throughout the vehicle. The number of relays may vary depending on the specific car model and its electrical system.
9. Which relay works both AC and DC?
Solid-state relays (SSRs) are designed to switch both AC and DC using the output of an SCR, TRIAC, or switching transistor. This allows them to perform the switching function without mechanical contacts.
10. What relay would prevent a car from starting?
If the starter relay fails, it can prevent the car from starting. Damage to the starter relay is usually caused by a short circuit due to a poor power connection on the starter.
During our car electrical system relay research, we found 24 car electrical system relay products and shortlisted 10 quality products. We collected and analyzed 5,786 customer reviews through our big data system to write the car electrical system relays list. We found that most customers choose car electrical system relays with an average price of $12.69.
The car electrical system relays are available for purchase. We have researched hundreds of brands and picked the top brands of car electrical system relays, including Derale, KC, Mopar, HELLA, Painless. The seller of top 1 product has received honest feedback from 137 consumers with an average rating of 4.4.
Robert Reyes is a dedicated writer from San Francisco with a bachelor of degree in mechanics and a bachelor of degree in marketing. He focuses on making some complicated topics simple and enjoys explaining complex and technical things in an easy-to-understand way.