The 4-pin relay is a crucial component in automotive electrical systems. It allows low-current circuits to control high-current devices such as headlights, fuel pumps, and cooling fans safely and efficiently. How It Works: Pin 85 & 86 (Coil): Activate the relay when current flows through the coil, creating a magnetic field. Pin 30 & 87 (Switching Circuit): Connects or disconnects the high-current load based on the coil activation. Applications: Headlights and fog lights Electric fuel pumps Cooli