TESTER for TRAILER sockets and connectors 7 + 13 pin adaptersThe wireless socket tester allows you to easily identify problems related to incorrect and faulty operation of trailer lighting. After pressing the test button, the tester analyzes the 6 positions of the diagnostic sockets. Identify lighting problems quickly and effortlessly. We especially recommend it to trailer owners, trailer rental points, car workshops, electricians, etc.The tester operates on a 9V battery (not included). If any indicator light does not light up, this indicates a malfunction of the corresponding cable. Stop light - red color Left turn signal - yellow Rear fog light - blue Left rear light - black Ground - white Right turn signal - green color Right rear light - brown color HOW TO DO A SOCKET TEST connect the tester to the cars socket - the lights are red turn on the given light (e.g. stop) the indicator lights up green if the indicator light of the light that is on lights up red, it means that the installation is faulty HOW TO DO A TRAILER TEST connect the plug to the tester press the yellow button on the tester green light indicates successful installation red light indicates incorrect installation or a burnt out bulb Includes: socket tester Adapter 13/7 Adapter 7/13