When it comes to diagnosing electrical issues in your car, testing the relays is often an essential part of the process. Relays are used in various components, such as the fuel pump, starter motor, and cooling fan, to control the flow of electrical current. A faulty relay can cause malfunctions in these critical systems, but with a multimeter, you can easily test whether a relay is working properly. This guide will walk you through the steps to test a car relay with a multimeter and help you determine if it’s time for a replacement.

Understanding Car Relays Before diving into the testing process, it’s important to understand the basic function of a car relay. A relay is an electrically operated switch that controls the flow of power to various parts of the vehicle. It consists of a coil, which, when energized, activates the switch inside the relay to connect or disconnect circuits. Relays usually have four or five pins, including two for the coil and others for the switch mechanism, such as normally open (NO) or normally closed (NC) pins. What You’ll Need： A multimeter (digital or analog) A 12V power source (for testing the relay)