The tester will automatically detect the pin position, the release time of the action, and the consistency of the relay in each test phase. If the tester lights up the green LED light, the relay is normal; if the red LED light is on, the relay is abnormal. First, clip the alligator clip of the tester to the car battery, the black clip on the negative pole, and the red clip on the positive pole. When the red LED light is on, it means the tester can start the test. Check the relay before testing. Select the appropriate socket according to the pins, insert the relay into sockets, press the "Test" button, and the tester will automatically detect the pin position of the unknown relay. Suitable for most general-purpose automotive relays on the market. When testing, it needs to be connected to the car's 11V-15V battery. The car battery must be a 12V battery, and the battery voltage must be between 11V-15V; 2. The applicable coil resistance is preferably above 20 ohms. Our automotive Relay tester is small and easy to carry around for on-the-go jobs or for easy storage. Its compact design allows easy use no matter where you are. With our patented design this relay tester will give you the results you need quickly and easily.