BHPerformance

06/24/2026

06/01/2026

🚗 How to Wire a Radiator Fan with a 4-Pin Relay: Step-by-Step Automotive Wiring Guide 🔧💡

Are you working on a DIY car project or fixing your vehicle's cooling system? Understanding how a 4-pin relay works is essential for protecting your electrical components and keeping your engine cool! 🌡️⚡

Here is a clear breakdown of the radiator fan wiring diagram shown above:

🔋 The Power Source & Safety:

The 12V car battery provides the main power.

A fuse is connected to the positive terminal to protect the circuit from short circuits and electrical damage. 🛡️

The ignition switch ensures the fan only receives power when the car is turned on, preventing battery drain. 🔑

🔌 The 4-Pin Relay Connections:

Pin 30: Connects directly to the fused 12V battery power.

Pin 87: Connects to the radiator fan positive terminal (delivering power when the relay clicks on).

Pin 85: Connects to the ignition switch for switchable power.

Pin 86: Connects to the temperature sensor, which acts as the ground switch.

🌡️ How It Works Automatically:
When the engine gets hot, the temperature sensor closes the circuit to the ground. This activates the electromagnet inside the 4-pin relay, closing the switch between Pin 30 and Pin 87, which instantly turns on the radiator fan to cool your engine! 🔄❄️

04/29/2026

04/29/2026

Engine replacement on this 2014 Chevy Silverado 1500

12/01/2025

We’re all hooked up with our chains and straps if you find yourself stuck in a ditch feel free to give us a call for a flat rate of $55. We will pull you out.
Servicing all of Lake County Illinois 24/7

12/01/2025

$45-100 depending on size of driveway

10/20/2025

Need your boat winterized… Dont worry call us and let us take care of it to ease the stress of winter preparation.

08/19/2025

No project is too big or small for us.💪 Out with the old in with the NEW!

08/19/2025

Has a dead battery ever left you stranded? With the cold season right around the corner it’s best to be prepared and confident in your vehicle. Call to schedule your next visit so we can keep you and your family safe on the road.