Features： 1、Function: Connect one end of the tester to the 13 hole plug of the trailer and the other end to the 13 hole socket of the car. The tester signal light will quickly show if the trailer or car coil is properly connected. 2、Material: The tester is made of copper, nylon and PVC circuit board materials, with high temperature resistance, low temperature resistance and acid and alkali resistance, which can ensure long term stable test performance. 3、Easy to Use: Simply connect it to the plug socket of the trailer or car, press the yellow button to test, and the LED light will quickly display the line status, convenient and quick. 4、Wide Application: The tester is applicable for a variety of 13 pin plugs and sockets, and can be used for different types of vehicles such as motorhomes, trailers, and automobiles to meet diverse needs. 5、Comprehensive Testing: The 13pin trailer plug tester quickly identifies issues with your trailer wiring, making it a critical tool for maintenance and safety. Specification： Material: Copper + Nylon + PVC Circuit Board Features: High temperature resistance, low temperature resistance, acid and alkali resistance Function: Test the electrical signal between the towing vehicle and the towed vehicle Usage Introduction: Trailer (can also be used for motorhomes): 2. Press the yellow button on the tester. 3. If all LED lights are lit up, it indicates that the wiring is normal. Each LED light has the following functions: 4. If none of the LED lights are lit up, the wiring connection is incorrect. Vehicle: 1. Connect the tester to the socket on the vehicle. 2. Press the yellow button on the tester. 3. If all LED lights are lit up, it indicates that the wiring is normal. 4. Test the function of each pin of each socket: Turn on the left turn signal, the 1st indicator light (Yellow) on the tester will light up. If the LED light is not lit, it means there is a wiring connection error or the wiring is damaged. 5. Repeat these two steps to test the right turn signal/fog light, etc. Package List： 1 x?13pin?Trailer?Plug?Tester