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

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.

Circuit tester helps to quickly identify problems with your vehicle's tow package wiring. Tests brake controller output, brake and battery voltages, and signal circuits. 20' Long cord plugs into 7-way connector for convenient, in-cab testing.

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.

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).

Test your wiring harness for shorts by plugging this tester in-line between your vehicle and trailer. LED lights illuminate with correct connection. Compact size allows easy storage.

Tester helps to quickly identify problems in your brake controller wiring. Tests brake controller output voltage, short circuit or overload, and connection to indicate the level of current in each circuit.