How to Wire LED Replacement Trailer Lights

Updated 05/31/2024 | Published 03/17/2017

Question:

I am replacing my old bulb type trailer lights with LEDs. Noticed that the LEDs have 3 wires each but I have a 4 wire system to match my truck. What is the wiring pattern or do I need a converter? Each LED is two positive and one negative wire.

asked by: Todd

Expert Reply:

If you are looking at and LED Trailer Tail Light like part # STL8RB, then you will not need a converter to make it compatible with the 4-Way Wiring Harness on your truck.

You will need to figure out the wiring on your trailer to make sure that you get all of the wiring done correctly. You can use a Circuit Tester # I26 for that purpose. All you have to do is hook up your new LED lights using the following information.

Brown is for tail lights
Green is for stop and turn
White is for ground

The 2 extra wires on the tail lights are white and they are used for the ground.

expert reply by: Jon G

John G.

4/7/2020

I am trying to convert my motorhome tail lights to LED. When I connect the wires White to ground, red to break/turn, and black to running light, the running lights do not come on. If I disconnect the break/turn light lead the running light comes on. I am replacing 4 lights and they all act the same. I am baffled and I would appreciate any help from you on this.

Chris R.

4/8/2020

First make sure that the white ground wire is securely attached to a clean, bare portion of metal on the trailer. If there is any paint or debris on the surface, sand it down completely, and then reattach the ground. When just one or another function doesn't work on a light - it almost always comes down to a weak ground connection. Please let me know if this doesn't resolve the issue and we'll go from there!

Brian

5/30/2024

Hi I have Maypole led lights but both indicators are coming on when I dictating left or right. I tried my trailer board with normal bulbs that works . I have checked the earth white wire and it is secured. I s there anything I can do to correct the fault? Thank you Brian

Jon G.

5/31/2024

@Brian If the lights work normally when you have normal bulbs installed then it sounds like you need to add the Load Resistor Kit for LED Turn Signals # DI34ZR for when you're using the LED bulbs. These make your system rear that there are standard bulbs installed as opposed to LEDs.