Troubleshooting LED Trailer Lights Blinking and then Not Working at all on a Boat Trailer

Updated 11/23/2012 | Published 11/21/2012

Products Featured in This Question

LED Combination Tail Light Kit for Trailers under 80" Wide - Submersible - Driver and Passenger

(3469)

$62.37

Hook Probe Circuit Tester

(66)

$13.85

Question:

my trailer lights worked fine for two weeks, then they started to blink like strobe when brakes are applied? only some of the leds would blink, not all. now they dont work at all.

asked by: Mike

Expert Reply:

The first thing I would do is check all of the ground locations on the trailer. If you have a ground that went bad it is very likely that at first it was causing the lights to blink and then finally failed completely.

If you check all of the grounds and they are connected securely to clean bare metal at each light and at the trailer coupler and your lights still do not work correctly, I would then check the vehicle side connector for proper function. Use a circuit tester, like part # PTW2993, and test the connector without the trailer attached. You should find that the exposed terminal is ground, the terminal adjacent to the brown wire should show power when the taillights are on, the terminal adjacent to the yellow wire should show power when the left turn signal and/or brakes are on, and the terminal adjacent to the green wire should show power when the right turn signal and/or brakes are on.

If the vehicle connector is functioning properly, test the wires going into the LED taillights for proper function. If you find that the wires going into the lights do not work correctly then you will need to check the trailer wiring for a short. If the wires going into the lights work correctly it is likely that the LED lights have gone bad and will need to be replaced.

One thing to keep in mind is that if you have a boat trailer, you should be using submersible LED lights, like the kit you referenced, # TLL9RK, to avoid shorting the light assemblies out if you forget to unplug the trailer lights when launching the boat.

expert reply by: Robert G