How To Wire a Trailer Tail Light with Yellow, Black, Red, and White Wires
Updated 02/09/2026 | Published 04/29/2019
Products Featured in This Question
Question:
I have taillights that have 4 wires blk red yellow and white. What is each color
asked by: William
Expert Reply:
The best way to find out what each wire is for on your tail light is to take a 12 volt power supply and apply that to each of the wires to see which bulb it illuminates. I cannot really give you an exact function for each color as it could vary from manufacturer to manufacturer.
With that being said, we have the Fusion LED Combination Tail Light Bar part # STL264RB which contains white, black, red, and yellow wires. The functions of these colors on this lights are as follows. This may be similar to what you have but it will be best to test with 12 volt power before making your connections.
Black: Tail
White: Ground
Red: Step/Turn
Yellow: Backup
Product Page this Question was Asked From
16 Gauge, 4 Conductor Bonded Parallel Wire - Per Foot
- Wiring
- Wire
- Bonded Wire
- 4 Wire
- 16 Gauge
- Deka
more information >
Continue Researching
- Search Results: self tapping screw
- Shop: Fusion LED Combination Tail Light Bar for Trailers Over 80" Wide - Submersible - Red/Clear Lens
- Q&A: Hardware to Install Fusion LED Combination Tail Light Bar On Trailer Frame
- Q&A: What Color Trailer Wires go to the Red, Black and White Taillight Wires
- Article: Trailer Wiring Diagrams
- Shop: Rambler ST205/75R15 Trailer Tire with Black Vesper Mod Wheel - 5 on 4-1/2
- Q&A: Standard Color Code for Wiring Simple 4 Wire Trailer Lighting
- Q&A: How To Wire LED Stop/Turn/Running Light
- Q&A: Wiring LED Tail Lights with Four Wires
- Shop: Loadstar ST205/75D15 Trailer Tire with Black Mod Wheel - 5 on 4-1/2
- Shop: etrailer Spare Tire Mount for Trailer with Angle-Iron Railing - Clamp On
- Search Results: trailer hitch
- Shop: Trailer Hitch
- Video: Firestone Ride-Rite Air Bags with Easy Mount Compressor Feature Breakdown
- Q&A: What is the Difference Between a Class II and a Class III Hitch?
- Search Results: trailer tires and wheels
- Shop: Trailer Wiring
- Q&A: Lug Nut Torque Chart for Trailer Wheels
- Video: A Look at the Power Mountain Tallboy 6 Ton Off-Road Bottle Jack with a Military Cargo Trailer
- Article: Brake Controller 7- and 4-Way Installation Kit (ETBC7)
- Shop: Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
- Search Results: trailer wiring
- Article: Wiring Trailer Lights with a 7-Way Plug (It's Easier Than You Think)
- Shop: Power Mountain Tallboy Off-Road Bottle Jack - 8-1/2" to 37-3/4" Lift - 6 Tons
- Shop: Suspension Enhancement
- Shop: Brake Controller
- Shop: etrailer Anti-Rattle Hitch Collar for 2" Hitch Receivers
- Article: How to Measure for Trailer Hitch Drop
- Search Results: trailer jack
- Shop: Base Plate for Tow Bar
on Wiring
Robert
2/7/2026
I have a 4 wire trailer light Black White Red Yellow My trailer wires are Brown Green Yellow White Witch wire goes where