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.

This circuit tester plugs into the 7-way connector on your vehicle. LED lights indicate which functions (brake, turn, tail, stop, reverse, electric brakes, and 12V) are properly working. Color-coded LEDs make it easy to distinguish each signal.

This circuit tester plugs into the 7-way connector on your vehicle. LED lights indicate which functions (brake, turn, tail, stop, reverse, electric brakes, 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.

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 circuit tester plugs into the 6-way connector on your vehicle. LED lights indicate which functions (brake, turn, tail, electric brakes, and 12V) are properly working.

This circuit tester plugs into the 5-way trailer connector on your vehicle. The bright LED lights indicate which functions (tail lights, brake lights, turn signals, and reverse lights) are working properly and which are not.

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).