Power Up Your Ride: Step-by-Step Guide on How to Wire Electric Radiator Fans

We all know that the engine is the heart of the car, so keeping it cool is crucial for performance and longevity. That’s when electric radiators come in, but how to wire electric radiator fans? Don’t worry! I’ll take you through the step-by-step process of wiring these components, from choosing the right fan to installing and wiring it correctly.

Wiring electric radiator fans is an effective way to improve engine cooling efficiency, prevent overheating, and extend the life of your vehicle. In our step-by-step guide, we cover everything you need to know about choosing, installing, and wiring electric radiator fans. By following our instructions and expert tips, you can power up your ride and keep your engine running cool and smooth.

What Are Electric Radiator Fans?

Electric radiator fans are devices that are used to cool the engine in a vehicle. They are designed to pull air through the radiator to help dissipate heat and are typically mounted behind it. Unlike mechanical fans, electric radiator fans are powered by electricity and are controlled by a thermostat or a fan switch. 

They can provide more precise control over engine temperature, consume less power, and produce less noise than mechanical fans. Electric radiator fans are commonly used in modern vehicles and are also popular among car enthusiasts who want to improve the cooling efficiency of their engines.

Why Are They Important Parts of Your Vehicle?

Electric radiator fans are an important part of your vehicle because they help regulate the temperature of your engine. Overheating is a common problem that can lead to engine damage or failure, not to mention the driving stress a malfunctioning vehicle can cause most drivers. 

Electric radiator fans can help prevent this by pulling air through the radiator to dissipate heat. They can also help improve fuel efficiency, reduce emissions, and increase engine performance. In addition, electric radiator fans are more precise and controllable than mechanical fans, which means they can be adjusted to provide optimal cooling under different driving conditions. 

ruck changed new radiator fan at the garage
These components are crucial to your vehicle’s cooling system

How to Wire Electric Radiator Fans – Step 1 Is Gathering Necessary Tools and Materials

No matter if you’re driving some of the most expensive cars in the world, it’s every driver’s responsibility to keep their vehicles safe for themselves and others. This means you need to maintain the internal and external components at the highest level. But, like every process you want to do with your vehicle, the first thing you need to do is gather the necessary tools and materials. Here’s a list of essential items I have at home and recommend getting:



  • Electric radiator fan(s),
  • Fan mounting kit(s),
  • Relay(s),
  • Fuse(s),
  • Wire connectors (spade connectors, butt connectors, ring terminals),
  • Electrical wire (16-18 gauge).

It’s important to use quality components when wiring electric radiator fans. Using subpar components can result in poor performance, unreliable operation, and even potential safety hazards. 

Cheap wires and connectors can corrode over time, leading to poor electrical conductivity and increased resistance, which can cause your fan to malfunction or fail. Using high-quality wires, connectors, relays, and fuses can help ensure reliable and safe operation and extend the life of your fan.

A man fixing a car
Have all the needed tools and materials before you actually begin

Step 2: Determine Fan Placement

The optimal fan placement for effective cooling is usually in front of the radiator, where they can pull cool air through the radiator and expel hot air out of the engine compartment. If you have limited space in front of the radiator, you can also mount the fan(s) behind the radiator, but make sure they are as close to the radiator as possible to maximize airflow. Here are some factors to consider when choosing the location for your fan:

  • Available space – The size and shape of your engine compartment will determine how many fans you can install and where they can be placed.
  • Airflow direction – It’s important to install your fan(s) in a way that allows them to pull air through the radiator, not push air towards it. This will ensure effective cooling and prevent overheating.
  • Clearance – Make sure there is enough clearance between the fan blades and the radiator to prevent them from hitting each other.
  • Obstructions – Avoid placing your fan(s) behind obstructions such as AC condensers or intercoolers, as this can reduce airflow and cooling efficiency.
  • Wiring length – Keep in mind the length of the wiring needed to connect your fan(s) to the electrical system, and choose a location that allows easy access to the wiring.

Step 3: Install Fan Relay and Thermostat

The purpose of a fan relay is to provide a high-amperage circuit to power the fan(s) while using a low-amperage signal from the thermostat to activate the relay. This allows for the safe and efficient operation of the fan without overloading the electrical system. The thermostat, on the other hand, is responsible for monitoring the temperature of the engine. 

It also sends a signal to the fan relay to turn on the fan(s) when the temperature reaches a certain threshold. Installing both the fan relay and thermostat is crucial for the proper functioning of your electric radiator fans and ensuring that your engine stays cool even in high-temperature conditions.

How Does the Installation Process for Fan Relay and Thermostat Go?

The installation process for a fan relay and thermostat typically involves connecting the relay to a power source, grounding the relay, and connecting the low-amperage signal wire from the thermostat to the relay. The thermostat is usually installed in a location that allows it to monitor the temperature of the engine, such as in the radiator or in the engine block. 

Once the relay and thermostat are installed, the fans can be connected to the relay using the appropriate wiring and connectors. And while you’re all about the relay, make sure you inspect other components, too. For example, if you want to know how to fix headlight wiring, malfunctioning relays could have a lot to do with it. 

A mechanic fixing a car
Make sure you know how to install the thermostat and relay

Step 4: Wire the Fans

Many experienced drivers actually don’t know how to wire twin electric radiator fans. First, you need to figure out what wiring and connectors you will need. From electrical wire (16-18 gauge) to wire connectors (spade connectors, butt connectors, ring terminals), you see why this process represents quite a stress for most car enthusiasts. But don’t despair because here are step-by-step instructions for wiring the fans:

Connect the Positive Wire From the Power Source to the Positive Terminal on the Fans

This can be done using a ring terminal or spade connector. For a parallel setup, connect each fan to its respective relay using the appropriate wiring and connectors. For a series setup, connect the positive wire from the power source to one fan, and connect the negative wire from that fan to the positive wire of the other fan, then connect the negative wire from the second fan to the relay.

Connect the Negative Wire From the Fan(s) To the Negative Terminal on the Relay

Doing this completes the circuit and allows the fan(s) to operate when the relay is triggered by the thermostat signal. Use wire connectors (spade connectors, butt connectors, ring terminals) to connect the wires securely, and wrap the connections with electrical tape or heat shrink tubing to protect them from moisture and corrosion. This can also be done using a ring terminal or spade connector.

Connect the Thermostat Signal Wire to the Signal Terminal on the Relay

This wire is typically a smaller gauge wire and may require a butt connector or spade connector. For a parallel setup, connect the signal wires from each thermostat to their respective relays. For a series setup, connect the signal wire from the thermostat to the relay, and connect the fans to each other and the relay as described above.

Connect the Relay and Battery

A power wire from the relay should now be connected to the battery or a fused power source. This wire should be a heavier gauge wire and may require a ring terminal.

Test the Wiring 

Turn on the engine and allow it to reach operating temperature. The fans should turn on automatically once the temperature reaches the threshold set by the thermostat.

Ensure All the Wiring and Connectors Are Secured

Secure the wiring and connectors with electrical tape or heat shrink tubing to prevent damage from vibration or moisture.

Step 5: Test the Fans

After wiring the electric radiator fans, it’s important to test them to ensure they are functioning properly. Testing the fans can help you identify any wiring or connection issues before they cause damage to the engine or the electrical system. It can also help you confirm that the fans are turning on and off at the appropriate temperature thresholds set by the thermostat. 

How to Test the Fans for Proper Function?

A simple way to test the fans is to turn on the engine and let it run until it reaches the operating temperature. At this point, the fans should turn on automatically and provide a noticeable increase in airflow and cooling efficiency. If the fans don’t turn on or don’t provide enough airflow, it’s important to troubleshoot the wiring and connections to identify and fix the problem. 

Although it could seem like a lot of work after installation, testing the fan is something you just have to do. Not only can you ensure that they are working properly, but you’ll be guaranteed that your engine stays cool and runs smoothly.

Returning home by car on sunny day
Test the wired fans and have a safe drive

When You Learn How to Wire Electric Radiator Fans, Your Ride Will Go Smoothly 

As you’ve seen, knowing how to wire electric radiator fans can truly make your trips easier and more enjoyable. Plus, it’s simple to do. Many car lovers believe that wiring electric radiator fans themselves is a great skill to have and a wonderful method of customizing their cars in a DIY manner. 

Changing the size of your radiator fan can also help you enhance its efficiency, thus impacting your driving performance in the best way possible. So don’t forget – knowing how to wire those fans allows you to finish any project with confidence, and the world-class results will definitely be worth it!