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.

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.