Installation of LED Trailer Tail Lights with 4 Wires

Question:

I have led trailer lights with a red, white and 2 gray wires coming out of the lights. How do these connect to my trailer/ vehicle wiring? The trailer is already wired and the old lights worked until I broke one so I am replacing both with the leds. Thanks

asked by: Douglas M

Expert Reply:

Without knowing exactly what lights you have, it is difficult to help based on color. Most of our LED lights use a pigtail with 3 wires # A47PB with the red being turn signal and brake, the black for tail/running light, and the white for ground. The only way to tell your unique light function is to connect the ground which I would assume is the white wire, and then test the other functions with 12V power. Then you will match the functions versus the colors.

Because you have an extra wire, that could be reverse light if your lights have that function, or the two wires may be connected. Some wiring systems have separate brake lights from turn signal thus the extra wire in some cases, where if your system has combined brake and turn signal those wires will be either connected together or one of them will not be connected at all.

I've attached a couple of articles to help.

expert reply by: Jason S