Electronic Trailer Wiring Tester

Hopkins Electronic Trailer Wiring Tester Quickly diagnose 4-way flat trailer wiring with the Hopkins Electronic Trailer Wiring Tester. Designed for tow vehicles, this compact tester plugs into a standard 4-way flat connector and uses bright LED indicators to verify turn signals, brake lights, running lights and ground connection. Easy-to-read LED indicators: Color-coded lights show each circuit status at a glance. Plug-and-play operation: No tools or batteries required—simply insert into the vehicle connector. Protective design: Doubles as a durable plug cap to keep the connector clean when not in use. Compact and portable: Small footprint fits in glove box or tool kit for roadside checks. Ideal for RV owners, boat trailers and utility trailers, the Hopkins tester helps prevent trailer lighting failures and improves safety before every trip. Reliable, simple and built to last.