how to test a car relay with multimeter： a comprehensive guide
Release time:2026-01-15 12:44:24
Testing a car relay with a multimeter is an essential skill for any car enthusiast or DIY mechanic. Relays are critical components in automotive electrical systems, acting as switches to control larger electrical loads such as headlights, starter motors, and electric windows. When they fail, they can lead to various electrical issues, making it necessary to diagnose and test them properly. This guide will walk you through the process of testing a car relay using a multimeter.
Understanding the Basics of a Car Relay
Before diving into the testing process, it's important to understand what a relay is and how it functions. A relay is an electromechanical switch that uses an electromagnetic coil to open or close contacts in a circuit. In a typical
Automotive relay, the coil controls the flow of electricity through the power circuit. When the relay is triggered (usually by a switch or the car’s computer), the coil pulls the contacts together, allowing current to flow.
Relays usually have four or five terminals：
Two terminals for the coil (usually labeled 85 and 86)
Chat Oline