How To Wire A Electric Fan Relay

How to Wire an Electric Fan Relay: A Step-by-Step Guide

Are you looking to improve your vehicle's cooling system efficiency and longevity? Installing an electric fan relay is a great way to achieve this. This comprehensive guide will walk you through the process of wiring an electric fan relay, ensuring your cooling system operates smoothly and effectively.

Understanding the Role of an Electric Fan Relay

Before diving into the wiring process, it's crucial to understand why an electric fan relay is essential. Unlike traditional engine-driven fans, electric fans are controlled by a relay, providing several advantages:

• Improved Engine Cooling: Electric fans can operate independently of the engine, ensuring optimal cooling even at idle or low speeds.
• Reduced Engine Load: By eliminating the parasitic drag of a mechanically driven fan, you reduce engine strain and improve fuel efficiency.
• Enhanced Controllability: You can precisely control the fan's operation based on engine temperature, preventing overheating and extending the lifespan of your engine components.

Tools and Materials You'll Need

Before starting, gather the necessary tools and materials:

• Electric fan relay: Choose a relay with appropriate amperage for your electric fan. Always check your fan's specifications for amperage requirements.
• Electric fan: Make sure it's compatible with your vehicle's cooling system.
• Wiring harness: This will connect the relay to the power source and the fan. You'll need appropriately sized wires for the amperage involved.
• Wire strippers/cutters: To prepare the wires for connection.
• Crimp connectors: To secure wire connections.
• Heat shrink tubing: To insulate and protect the connections.
• Soldering iron and solder (optional): For a more robust and secure connection.
• Electrical tape: To secure and insulate connections, especially if not using heat shrink tubing.
• Circuit tester: To verify power and ground connections.
• Screwdrivers: To secure the relay and any other components.
• Zip ties: For neatly organizing wires.

Step-by-Step Wiring Instructions

The specific wiring diagram will vary slightly depending on your relay and vehicle. However, the general principles remain consistent. Always consult your relay's instructions for detailed guidance.

1. Locate Power and Ground Sources: Identify a suitable power source (usually a switched power source, meaning it's only live when the ignition is on) and a reliable ground point. A switched source is recommended to prevent your battery from draining if the fan is left running accidentally.

2. Locate the Fan's Power and Ground Wires: Identify the power and ground wires coming from your electric fan.

3. Connect the Relay's Terminals: This is the core of the installation. Refer to your relay's diagram for terminal identification. Common terminal designations include:

• Terminal 85 (Coil): Connected to ground.
• Terminal 86 (Coil): Connected to the switched power source (ignition). This activates the relay.
• Terminal 30 (Power): Connected directly to the battery's positive terminal. This provides power to the fan.
• Terminal 87 (Output): Connected to the fan's positive wire.

4. Connect the Fan's Ground Wire: Connect the fan's ground wire to a reliable ground point on the vehicle's chassis.

5. Secure the Relay and Wiring: Securely mount the relay in a safe and accessible location, ensuring the wires are neatly organized and secured using zip ties.

6. Testing the System: With the ignition turned on, the electric fan should now turn on when the relay is activated (usually by a temperature sensor or a switch). Use a circuit tester to confirm power is reaching the fan.

Troubleshooting Common Issues

If your electric fan isn't working:

• Check the fuses: Ensure all related fuses are intact.
• Verify power and ground connections: Use a multimeter to check for voltage at each terminal of the relay and the fan.
• Inspect the relay itself: It's possible the relay has failed. Try swapping it out with a known working relay.
• Check the wiring: Look for any loose or damaged wires.

Conclusion

Wiring an electric fan relay can significantly improve your vehicle's cooling system. By carefully following these instructions and troubleshooting potential issues, you can enjoy the benefits of a more efficient and reliable cooling system. Remember, safety is paramount. If you're uncomfortable performing electrical work, it's best to seek professional help.