Testing a car relay with a multimeter is a crucial skill for any car enthusiast, mechanic, or DIYer. A malfunctioning relay can cause issues in various electrical systems in your vehicle, such as the headlights, fuel pump, and air conditioning system. The ability to test a relay ensures that you can quickly diagnose electrical problems and avoid unnecessary replacement of expensive parts. In this article, we’ll guide you through the process of testing a car relay with a multimeter.

What Is a Car Relay? A relay is an electrically operated switch that controls the flow of current to various components in a vehicle. It is typically used in circuits that require a higher current than a switch can handle. The relay has an electromagnet that, when powered, either closes or opens a circuit. This allows it to control larger electrical systems with a smaller current, making it a vital component in modern vehicles. Car relays usually have five pins: Pin 30: Common (Power Input) Pin 87: Normally Open (Output) Pin 87a: Normally Closed (Output when relay is not energized)