Expand the wires, connect the red clip to the positive electrode of the car battery, and connect the black clip to the negative pole terminal of the car battery. the "Positive Extreme" button. The LED light up.The terminal to activate the component.If the LED turns green and the beeurizer makes a sound, stop the test and check whether the component is defective, or whether the current rated value of the component is higher than the current rated value of the tester. The power circuit probe tester uses advanced high -sensitivity probes to provide you with fast and accurate testing, which can a lot of time to the car wiring circuit failure, quickly and accurately locate the fault line and its fault point.The tester also has an overload protection device. When the current exceeds 7A, the circuit breaker inside the device automatically automatically automatically automatically automatically automatically automatically reminds. The power circuit probe tester is made of insulating material and high -quality Metal cutting end to help you quickly identify the positive and negative poles of vehicle and cables and plugs.When the tip of the probe is exposed to the positive electrode, the red light is on.When the tip of the probe is exposed to the negative electrode, the green light is on.The power circuit probe tester is also used to check the continuity of relay, diode, switch, fuse and circuit. The testor of the car power supply circuit probe can activate components inside and outside the vehicle's electrical system, making it very suitable for professional or car enthusiasts.The LED indicator and the bee tweeter alert whether there are defects or the rated current of the component than the car test light. Note: This circuit tester cannot be used on the 110/220V system. It can only be used on the DC 6-24V system.Do not use it under AC voltage.If you have any questions, please contact us in time. We provide technical support within 24 hours to solve the problem in time! Colour:B:Blue Material:Metal + Plastic Package Contents: 1set x automotive relay tester Only the above package content, other products are not included. Note: Light reflection and different displays may cause the color of the item in the picture a little different from the real thing. The measurement allowed error is +/- 1-3cm.