Oyviny 3-in-1 Trailer Plug Tester 4/5 Pin Flat & 7 Pin Trailer Light Tester with Double-Sided LED Indicators, 5 Way & 7 Way RV Trailer Connector Tester, Not Suitable for Vehicle with Lamp Out Sensor

3 in 1 Design: This trailer wiring tester combines both 5 way and 7 way trailer tester, allows you to test the 4 pin flat, 5 pin flat and the rv blade 7 way trailer connectors, easy and quick to test trailer circuits on most trucks; Note: This trailer tester does NOT work with vehicle has a lamp-out sensor, such as 2020+ GMC, Chevrolet, BMW, VW, Audi, Mercedes-Benz, Porsche etc. | Upgraded Double-Sided LED Indicators: 5 pin flat & 7 pin trailer plug tester designed with LEDs on both sides for easy reading, Unlike the other testers only have one side leds, which make it hard to read; A great tool to help troubleshoot issues or verify you have install or fixed your trailer plug correctly | 6 Light Functions: Versatile trailer socket tester can be used to test 6 separate trailer light functions, quickly confirm the functionality of taillights, brake lights, reverse lights, turn signals, electric trailer brakes and 12V auxiliary power on your vehicle | Bright LED Indicators: Multi-function trailer hitch tester equips a LED light for each electrical function; Plugging the light tester and check, you can easily read the green LEDs and find out which wiring has a problem | Durable Construction: For long-lasting use, this 7 pin trailer plug tester is made from durable ABS plastic, which will never rust or corrode, Tin-Plated copper terminals makes great conductivity | Simple to Use: No batteries or wiring needed; Trailer light checker is easy to use, ergonomic design is convenient for plugging in or unplugging; Widely used to test trailer light circuits on most Trucks, Boats, Trailers Campers, Caravans, Food Vans and other Towed Vehicles