25' 4-Way Flat Trailer Light Wiring Harness Kit – Complete 4-Wire Connector
This 25-foot trailer light wiring harness kit connects trailer lighting systems to the tow vehicle using a standard 4-way flat connector. The bonded four-wire design simplifies installation and provides reliable electrical connections for tail lights, brake lights, and turn signals.
The extended 25-foot harness length works well for most small to medium utility trailers, boat trailers, and cargo trailers.
R&P Knowledge Hub
The 4-way flat connector is the most common trailer wiring configuration used for light-duty trailers. It provides four basic lighting functions: ground, tail/running lights, left turn/brake, and right turn/brake.
Bonded wire harnesses keep the four conductors attached together, making routing along the trailer frame easier while reducing tangling and wire damage.
Highlights
| Feature | Description |
| Function | Connects trailer lights to tow vehicle using standard 4-way flat plug |
| Length | 25 feet — suitable for most small to medium trailers |
| Design | Color-coded bonded wire simplifies routing and installation |
| Durability | Flexible insulation resists cracking, tangling, and weather exposure |
Specifications
| Specification | Detail |
| Part Number | 16977 |
| Connector Type | 4-Way Flat Plug (Male & Female) |
| Harness Length | 25 feet |
| Wire Gauge | 18 Gauge Bonded Wire |
| Functions Supported | Tail lights, brake lights, left & right turn signals, ground |
| Wire Color Coding |
White – Ground Brown – Tail / Running Lights Green – Right Turn / Brake Yellow – Left Turn / Brake |
What's Included
| Item | Description |
| Harness Kit | (1) 25-ft bonded 4-wire harness with molded 4-flat connectors |
| Compatibility | Works with standard 4-way trailer light systems |
Fitment & Notes
| Category | Details |
| Fitment | Universal for most light-duty trailers including boat, cargo, and utility trailers |
| Installation | Bonded wire harness simplifies routing along trailer frame |
| Safety | Test all trailer light functions after installation |
