Turn Signals and Tail Lights Blink on Trailer After Installing LED Bulbs

Question

Question:

I have a small trailer with only two tail lights. Each tAil light takes one 1157 bulb. Incandescent bulbs work fine for all functions: Brake, turn, hazard flash and park. LED bulbs do not work correctly. When I use one turn signal, the turning bulb blinks normal ... But ... The other bulb also blinks, albeit a little less bright. If I have one LED and one incandescent, setting the LED to turn causes the incandescent to also blink but very very dimly. Setting the incandescent to turn does not make the LED blink. What might cause this? The LED bulbs work fine for the other functions: Brake, hazard flash and park. It seems the trailer wiring is fine and its the LED bulbs at fault?

asked by: Peter

0

Expert Reply:

It sounds to me that when you activate the left turn signal, the tail light signal (lower intensity signal) on the right tail light blinks. My first thought is there is a wiring or ground issue somewhere on the trailer. It may have not been immediately evident with the incandescent bulbs because they require more power to function than LED bulbs. LED bulbs require only a fraction of power to function and any type of power issue could trigger other lights to function.

To troubleshoot this issue, I would recommend starting at the trailer connector. Make sure it is ground to a clean, bare metal surface on the trailer frame. Next, inspect the connector for any corrosion or bent pins and repair or replace as necessary.

After that, inspect the stop, turn and tail light circuits on the trailer looking for any loose, damaged or frayed sections that could cause two circuits to touch. I would recommend using a circuit tester like part # 3808 to probe the different light circuits to see where the power issue starts. I have attached an FAQ article on trailer wiring that you should find helpful when inspecting the trailer wiring.

Finally, check the tail light assemblies themselves. Ensure they are grounded to a clean, bare metal surface. Some lights do not have a separate ground wire and ground through the mounting studs.

If you cannot find the problem or a possible solution after following these steps, let me know what you come up with and we can do further troubleshooting.

expert reply by: John H

0

Answer 1

You will wire a load resistor into the wiring of each light socket that has an LED bulb and flashes. So basically you will need to wire a load resistor into any bulb that blinks or has a dual intensity feature that lights up when the brakes,…

view full answer...

Answer 2

If both turn signals blinking at the same time is a new problem that has occurred after the harness had worked fine before, there are a couple of possibilities that may be causing the issue. First, the easiest thing to check are the trailer…

view full answer...

Answer 3

The most likely cause for the incorrect behavior of your trailer lights, where activating one turn signal causes all trailer lights to blink, is an insufficient ground (or a short to ground) on either the vehicle or the trailer. Since you re-wired…

view full answer...

Answer 4

It sounds like you have a ground issue. Ground problems show up when there is more load on a system. In this case with the running lights on there is more load on the system when you go to using the turn signals or brakes. You will want to check the…

view full answer...

Answer 5

A trailer that is over 80 inches wide is required by DOT regulations to have rear clearance lights. An over 80 inch taillight kit, like part #TL16RK, will have the side clearance light built into it. An under 80 inch taillight does not have the…

view full answer...

Answer 6

In order to determine the torque rating for the lug nuts on your trailer you will need to know check out the chart I attached that shows all of the torque specs for all the trailer lugs available based on stud size, wheel material and wheel size.

view full answer...

Answer 7

The difference between an load range C and load range D tire in the same size is the capacity and psi rating. The two tires will still have the same dimensions and fit on the same wheel. The D rated tire has a higher capacity. For a ST175/80D13 like…

view full answer...

Answer 8

Load range B trailer tires are going to have a lower capacity than C load range tires. Basically that, psi rating, and the ply rating are the only differences. A higher load range tire would last a little longer than lower load ranges of the same…

view full answer...

Answer 9

To determine the size of the hub assembly you need to purchase you have to determine which bearings are in the old assembly. If the old assembly has L44649 inner bearings, you would use the hub you chose #8-258-5UC1. If the inner bearings are marked…

view full answer...

Answer 10

Even though I cannot comment specifically on the grease you used because I am not familiar with it, I can tell you the best grease for trailer bearings is a a grease with a rating of GC-LB, which just means it is made to withstand very high…

view full answer...

Answer 11

What you are describing is normally the result one 1 of 3 issues: First, there could be some corrosion in or on the connectors on the vehicle or trailer side or both. Second there could be a bad ground. Bad grounds can cause all sorts of bizarre…

view full answer...

Turn Signals and Tail Lights Blink on Trailer After Installing LED Bulbs

Product Page this Question was Asked From

Featured Help Information

Miscellaneous Media

Continue Researching