Hello Dylan. Without having a vehicle to connect to, the only way to properly test your trailers 7-way is to use a tester like the Tekonsha # 8010 or the Hopkins Tow Doctor # HM50928. These testers provide a power source and will allow you to test all of the functions easily by yourself. These testers are expensive though, so if it were me. I would go ahead and put that money towards installing a 7-way on the vehicle so you can test it that way. If you can let me know the year, make and... view full answer...