High PerformanceAutomotive trailer socket tester is made of high quality ABS and copper material, frosted surface, durable and reliable, ensures maximum strength and durability for long lasting use. Such a handy trailer tester tool you will need. Packing list: K4216; 1 * 7-Pin Trailer Tester Tool; 1 * English GuideApplication & SpecificationThe trailer tester socket is widely suitable for caravans, RVs, RVs, vehicles, trucks, trailers, etc. 20*5*4cm; Battery type: 9V (not included, you need additional purchase) Battery type: 9V (not included, you need additional purchase) Package size: 20 * 5.5 * 4.5cm / 7.9 * 2.2 * 1.8in Package Weight: 194g / 6.8ozTest functionThis trailer hitch socket has one side to connect the 7-pin socket of a trailer and another side to connect the 7-pin socket of a car. This tester quickly indicates whether a fault is in the car wiring or the trailer wiring, which can effectively test the problem of the 7-pin plug and socket connection.Reliable QualityThe 7 pin trailer tester with safe and reliable performance, reasonable design. Skillful appearance, convenient use. Reliable quality and delicate workmanship persuade you to take this one to replace the old one. Specifications: Main Material: ABS and Copper Color: Black Item Type: Diagnostic Tools Item Name: Trailer Tester Size: approx. 20*5*4cmProduct Operation Guide: Trailer Put the plug into the tester connection. Press the yellow button on the side of the tester. The function of each LED is (1724 compatible): 1. left indicator (yellow); 2. fog light or 12V (blue); 3. ground (white); 4. right indicator (green); 5. right rear light (brown); 6. left brake light (red); 7. left rear light (black). Attention: Pin 2 can be used either for a warning fog lamp or for a permanent 12V connection. If an LED does not light up, the corresponding wire is defective. If all the LEDs do not light up, the ground wire is damaged or all the bulbs are faulty. Car, Camper 1. Put the tester into the car socket. 2. Press the yellow button on the side of the tester. 3. If the wiring is good, all LEDs light up. Repeat step 4 as before. You can also test the functions of each pin in the socket. 1. Turn on the left indicator (after turning on the ignition key). 2. The corresponding LED should flash with the same frequency. If not, the left indicator wiring is faulty/broken. 3. Repeat steps 1 and 2 for the right indicator, tail light, fog light and brake lights. With a +/- 4m extension cable, you can more easily test the driver's seat functions.