How to Use a Taillight for Both Third Brake and Running Light Functions

Question:

I would like the third brake light to also have the running light tail light function. So could I add the converter for the brake light and then just run the brown tail light wire to the brake/tail light? Thank you!

asked by: Jack

Expert Reply:

In order to use a third brake light for both brake and running light signals, you would need to use a light with turn, brake, and running light capabilities such as the Thinline LED Trailer Tail Light part # STL59RB. As most trailers are a 3 wire system you would also need to use the Vehicle to Vehicle Tail Light Converter part # 118158 to separate the brake signals from turn the signals.

In order to install the light you would first need to take the ground wire (white) from the taillight and attach it to a clean bare metal surface. You would then take the brake light wire (black) from the taillight and connect it directly to the running light wire (brown) on the trailer. Finally, the turn signal light wire (red) from the taillight will need to be attached to the red wire on the converter box. The other two yellow and green wires on the output side of the convert box will not be used. I also recommend using the Deka Heat Shrink Butt Connectors part # DW05743-5 to make these connections.

I have attached a review video of both the light and converter box for you as well.

expert reply by: Conner L