How to Use a Taillight for Both Third Brake and Running Light Functions
Updated 06/22/2024 | Published 11/03/2017 >
Products Featured in This Question
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.
Product Page this Question was Asked From
Thinline LED Trailer Tail Light - Stop, Tail, Turn - Submersible - 9 Diodes - Red Lens
- Trailer Lights
- Tail Lights
- Brake/Tail/Turn
- Strip Light
- Surface Mount
- Submersible Lights
- LED Light
- 12-1/2L x 1W Inch
- Red
- Optronics
more information >
Featured Help Information
Miscellaneous Media
Continue Researching
- Q&A: Replacement Foot Base for Thule Tracker Roof Rack
- Shop: Replacement FootBase Thule Tracker Roof Rack FitKits TK1, TK2, TK6, TK7, TK8, TK9, TK10, TK11, TK12
- Q&A: Adapter for Truck Wiring To Wire Third Brake Light of Camper Shell
- Shop: Thinline LED Trailer Tail Light - Stop, Tail, Turn - Submersible - 9 Diodes - Red Lens
- Q&A: How to Wire a Third Brake Light on Trailer
- Q&A: Third Brake Light Still Flashes With Pacer Logic Module Installed
- Video: Complete Breakdown of the 3rd Brake Light Logic Module
- Shop: Replacement Foot Base for Thule Tracker Roof Rack Fit Kit TK2
- Shop: 3rd Brake Light Logic Module
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Search Results: trailer hitch
- Video: Firestone Ride-Rite Air Bags with Easy Mount Compressor Feature Breakdown
- Shop: Trailer Hitch
- Article: Trailer Wiring Diagrams
- Video: How to Choose a Trailer Brake Controller
- Shop: Trailer Wiring
- Search Results: trailer tires and wheels
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Q&A: Installation Time for Blue Ox BX1128 Flat Tow Base Plate Kit for 2016 Jeep Grand Cherokee
- Video: An In-Depth Look at the Roadmaster Diode 7-Wire to 6-Wire Flexo-Coil Wiring Kit
- Search Results: trailer wiring
- Q&A: Replacing 6-Way on Trailer With 7-Way Connector
- Shop: Power Mountain Tallboy Off-Road Bottle Jack - 8-1/2" to 37-3/4" Lift - 6 Tons
- Shop: Suspension Enhancement
- Article: How to Measure for Trailer Hitch Drop
- Shop: Brake Controller
- Search Results: trailer jack
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Shop: etrailer Anti-Rattle Hitch Collar for 2" Hitch Receivers




Ryan
6/21/2024
So ,2019 ram has trailer connector in bed. I added topper to truck. Wanted to add power for brake light,also power to dome light Possibly utilizing 7 pin 78119 connector! Which I have. The third brake light ,and dome light have a male 3 pin flat connector already on the wires I would appreciate guidance.