LIMICAR 35ft 4-Wire Trailer Wiring Harness — 4‑Pin Flat, 42in Ground, SAE J1128

LIMICAR's 35FT 4-wire trailer wiring harness is a full-length, 4-pin flat kit that supplies tail, stop/turn and ground connections for trailers both under and over 80" wide.

Whether you’re wiring a boat trailer, utility trailer or ATV hauler, this 35-foot, color-coded harness gives enough length to run down each side of the trailer tongue and reach both lamp circuits without splicing extra cable on the trailer body. Built to SAE J1128 low-voltage standards with 18 AWG bonded conductors, the kit simplifies a basic four-function hookup using a 4-way flat connector and includes an extended 42" white ground lead for reliable grounding.

How does this harness handle different trailer widths and layouts?

The 35-foot wire length is intended to accommodate trailers that are either under or over 80" wide by allowing the jacket to split at the tongue and route down each rail. The white ground lead is 42" so you can reach common grounding points while the other conductors run to left and right lamp assemblies.

• 35' main harness for long tongues and wide trailers
• Split design lets you run wires down both sides of the trailer
• 42" white ground wire reaches common frame grounding locations

What wiring colors and functions are included, and how do I identify them?

The harness uses standard color coding to match most vehicle 4-way flat plugs and simplify installation. Each conductor is bonded and labeled by color so you can quickly identify ground, tail, driver-side and passenger-side circuits without guesswork.

• White — ground/negative (42" lead)
• Brown — tail and running lights
• Yellow — driver-side stop/turn light
• Green — passenger-side stop/turn light

Is this harness durable enough for marine or heavy-duty use?

This kit is constructed to meet SAE J1128 low-voltage cable standards and uses quality materials suited for exposed trailer environments. While it’s not a sealed multi-conductor assembly for submerged use, the bonded 18 AWG conductors and rugged outer jacket stand up to normal road and marine trailering conditions.

• 18 AWG bonded wires for consistent conductivity
• SAE J1128 compliant for low-voltage trailer wiring
• Outer jacket protects conductors from abrasion and weather

How easy is installation and what vehicles are compatible?

Installation is straightforward for anyone comfortable routing wiring and securing connectors; the harness terminates in a standard 4-way flat plug that mates to most tow vehicles’ 4-pin sockets. It fits trailers using a 4-way flat system—confirm your tow vehicle has a 4-way plug before ordering, and note this kit is not intended for motorcycle trailer wiring.

• Plugs into standard 4-way flat trailer connector
• Color-coded conductors speed up hookup and troubleshooting
• Suitable for boat, horse, ATV, and general cargo trailers

Who this is for: This LIMICAR 35FT 4-wire harness is for DIY trailer owners, fleet maintenance staff, and boaters who need a reliable, full-length 4-pin wiring solution that reaches both sides of the trailer without excessive splicing. Choose this kit if you want a SAE-compliant, color-coded 4-way flat harness with an extended ground lead for dependable lighting and turn-signal connections on a wide range of trailers.