With the 7-pin plug tester 343524 from ProPlus, you can check the lights of your vehicle and synchronise them with the ones on your trailer. First you connect the tester to the vehicle’s power socket. If the vehicle is fitted with a 13-pin socket, a 13- to 7-pin adapter must be used. Then turn on the ignition and test all functions with the aid of a second person. If the socket is properly assigned, the corresponding indicator lights up (When testing the direction indicator, the light will also blink). Delivery includes 1 tester and 2 adapters.