Testing a car relay with a multimeter is an essential skill for anyone dealing with automotive electrical systems. Relays play a crucial role in controlling circuits by acting as switches that allow a small current to control a larger one. If your car is experiencing electrical issues, such as non-functioning lights, air conditioning, or even the engine, a faulty relay could be the culprit. Fortunately, with the right tools and a bit of know-how, you can test a relay yourself, saving time and money on repairs.

What is a Car Relay? A car relay is an electrical device that allows a low current circuit to control a high current circuit. Relays in cars are commonly used for controlling lights, horns, fuel pumps, and various other electrical systems. Relays have a coil and a set of contacts that open or close when the coil is energized, thus completing or breaking the circuit. Over time, relays can wear out, and when they do, the electrical components they control may stop working. Tools You’ll Need Before diving into the testing process, you’ll need to gather a few essential tools： Multimeter： Preferably a digital multimeter that can measure resistance (Ohms), voltage, and continuity.