This LED tester tests all lighting functions necessary for safe driving on vehicle trailer light sockets and trailer plugs. The LED indicates the respective defective wire colour. It checks all 7-pin sockets and plugs and includes two adapters for testing all 13-pin sockets and 7-pin plugs. Both adapters can also be used between a 13-pin towing vehicle and a 7-pin trailer and vice versa. Power consumption via 9-V block battery (not included). https://elecena.pl/product/18366695/2003-led-vehicle-light-tester 2021-05-06 https://elecena.pl/product/18366695/2003-led-vehicle-light-tester 2025-12-10