Circuit tester plugs into your 4-way flat trailer wiring harness and identifies lighting problems. Labeled LED lights illuminate to show which functions are working properly.

This tester helps you to quickly identify problems in your trailer wiring. It tests the left turn, right turn, tail/marker, brake and backup circuits to indicate the level of current in each circuit. It also tests the voltage of the trailer battery.

This circuit tester plugs into the 7-way connector on your RV. LED lights indicate which functions (brake, turn, tail, stop, reverse and 12V) are properly working.

A circuit tester that plugs into the 7-way trailer connector on the vehicle and emulates a trailer. The lights let you know what functions (brake, turn, tail, stop, reverse and 12V) are working properly and what functions are not.

Use this tester to check the connection between your tow vehicle's 7-pole, blade-style connector and your brake controller. Tester emulates trailer to confirm connectivity. LED lights illuminate to show each function is working.

This Brophy electrical tester works for both 4- and 5- way flat trailer wiring harnesses.

Circuit Tester Kit

A circuit tester that plugs into the 6-way trailer connector on the vehicle and emulates a trailer. The lights let you know what functions (brake, turn, tail, stop and 12V) are working properly and what functions aren't.

Digital multimeter (DVOM) measures AC and DC voltage, amperage and ohms. The easy-to-read LCD screen provides accurate data. Test leads and battery included.

This adapter lets you test a 7-way, round-pin, vehicle-end connector to ensure that all the wiring functions are working properly. Plugs into the extension cord on your Hopkins Tow Doctor wire harness tester (HM50918; sold separately).