Troubleshooting Trailer Left Turn Signal Light That Does Not Blink

Updated 04/09/2015 | Published 04/08/2015

Products Featured in This Question

Optronics LED Trailer Tail Light - Stop, Turn, Tail - Submersible - 10 Diode - Oval - Red Lens

(2237)

$17.39

Hook Probe Circuit Tester

(70)

$12.41

Question:

I have work sport trailer and my left turn signal doesnt want to work but all other lights do even when I have my four ways on the left tail light will flash but when signaling to turn left .what would be my best option to replace the tail light for it my have a bad ground on it

asked by: Ryan M

Expert Reply:

Its usually easiest to disconnect the trailer from the vehicle and test the trailer functions directly by connecting 12V power from the vehicle (or another) battery right to the various circuits on the trailer plug. This way of testing isolates the trailer from any issues that might be present in the vehicle wiring, such as a mis-wired connector.

If you do this and the trailer light does not do what it is supposed to do, then check both your main trailer connector ground and the problem light's ground. Ground connections need to be made to clean bare metal surfaces. This includes both the main trailer ground and the wired or mounting stud ground on the light itself.

The linked article on trailer wiring will help you with additional troubleshooting steps.

You can also try testing the one light all by itself, again by connecting it directly to the 12V power source. If the unit fails to operate properly in this test, then you probably need a new light. If the light does work right after either of these tests, then you will want to test your vehicle connector for proper signals using a tester like # PTW2993. Please see the linked video for an example of how to use the tester.

If you do need a replacement, you can use the link provided to see all trailer taillights, we offer. You can use the filters on the page to choose the shape, size, and bulb type you need.

expert reply by: Adam R