4-Way Flat Trailer Wiring Tester, Double End Male&Female Plug

4-Way Trailer Tester: This 4-pin trailer plug tester is specially designed for diagnosing trailer lighting issues. It can connect to standard 4-pin trailer wiring harnesses, accurately locate system fault points, and test trailer lights, avoiding blind troubleshooting and improving the accuracy and efficiency of fault diagnosis. | Plug & Play: This trailer light line tester is easy to operate. Simply insert the tester into the 4-pin flat trailer connector on the trailer to easily check the working status of the circuit wiring and test whether taillights, turn signal lights, etc., are operating normally. When the circuit is operating normally, all LED indicators will light up. | Bright LED Indicators: This 4-pin trailer plug tester is equipped with LED indicators. Lights of different colors represent different circuits, allowing you to easily identify faulty circuits by reading the LED indicators and saving maintenance time. | Sturdy Construction: This trailer light line tester is made of high-quality ABS material, which is tough, wear-resistant, corrosion-resistant, and not easily damaged, ensuring long-term use. The copper terminals offer good electrical conductivity, enabling stable transmission of test signals. It also comes with a dust cover to block dust and moisture, extending the tester's service life. | Wide Application: This 4-pin trailer plug tester has a wide range of applications, suitable for various vehicles such as cars, boats, and trailers. It is compact and does not take up much space, allowing you to easily store it in a toolbox or any portable location.