Using Circuit Tester, Part # 40376 To Determine Why Left Turn Signal on Trailer is Not Working

Expert Reply:

After checking the bulb and making sure that the socket is not corroded or damaged, you will have to trace the wire for that fixture, looking for any pinched or broken wires. Also look for cracked or worn wire insulation that would allow the copper conductor to come into contact with any metal on the trailer. I would recommend using a circuit tester, such as our part # 40376, and start tracing the circuit from the trailer connector all the way back to the light fixture. This will help narrow down where the fault in the circuit is located.

expert reply by: Mike L