Seamaka Trailer Wiring Harness 26FT 4-Way Flat 5-Wire Jacketed Cable (16AWG) — Extra Ground, Weather-Resistant

The Seamaka 26FT 4-Pin 5-Wire Trailer Wiring Harness is a 26-foot, jacketed 4-way flat cable with an extra ground wire that connects taillights, turn signals and brakes for trailers, RVs and boats.

This heavy-duty trailer wiring kit provides a long-reaching, color-coded connection between your tow vehicle and trailer lighting system. Built with 16AWG copper conductors inside a thick PVC sheath, the cable resists wear, moisture and temperature extremes while giving clear signal paths for power, ground and light circuits. It’s intended for installations that need a 4-way flat plug with five conductors (the extra wire helps ensure a solid ground or can feed a separate circuit), and it’s compatible with common trailer types including boat trailers, utility trailers, ATV carriers and horse trailers.

How will this harness simplify my trailer lighting hookup?

Installers and DIY owners will find the Seamaka harness straightforward because its plug and wiring colors match standard trailer wiring conventions. The 4-way flat connector plugs into most vehicle sockets while the extra 2.5-foot ground lead allows reliable chassis grounding or pig-tail attachment to trailer bulbs.

• 26-foot main cable reaches most towing configurations without splicing.
• Color-coded wires make matching circuits faster and reduce mistakes.
• 2.5-foot ground wire gives flexible grounding options and secure attachment.
• 4-way flat plug fits standard 4-pin trailer sockets for turn/brake/taillight/power.

Is the cable durable enough for marine or outdoor use?

The harness uses copper conductors inside a thick PVC outer jacket to resist abrasion and exposure. Rated for a wide working temperature range and 300V, the cable is built for long-term outdoor service where weather, vibration and road debris are common.

• 16AWG copper core for reliable conductivity and signal strength.
• Thick PVC insulation and outer sheath protect against chafing and moisture.
• Temperature tolerance from -22°F up to 221°F suits varied climates.
• Jacketed design prevents shorting and extends service life on trailers.

What vehicles and trailers work with this 4-way, 5-wire harness?

This wiring kit is designed for most trailers and tow vehicles that use a 4-way flat connector standard. It’s a good match for boat trailers, utility trailers, horse trailers, and ATV carriers where you need standard lighting circuits plus a separate ground or auxiliary feed.

• Compatible with 4-way flat trailer plugs on trucks and SUVs.
• Suitable for boat trailers, cargo trailers, horse trailers and ATV trailers.
• Useful when an additional ground or shared power feed is required.
• Works for rewiring or replacing worn factory trailer cable assemblies.

How easy is it to install and maintain the Seamaka harness?

Installation is straightforward for anyone comfortable with basic trailer wiring: plug the 4-way flat connector into the vehicle socket, route and secure the 26-foot cable along the trailer frame, and attach the ground lead to a clean metal surface. Routine maintenance is minimal—inspect connectors for corrosion and the jacket for wear; replace if insulation is damaged.

• Plug-and-play 4-way flat connector reduces installation time.
• Color-coded wires simplify splicing or hook-ups to trailer lights.
• Secure ground wire attachment improves electrical reliability.
• Periodic visual checks keep connectors free of corrosion and ensure safety.

Who is this for: The Seamaka 26FT 4-Pin 5-Wire Trailer Wiring Harness is aimed at trailer owners, boaters, and do-it-yourself mechanics who need a long, rugged, color-coded cable to restore or upgrade trailer lighting. It’s best for users who want an affordable, ready-made 4-way flat solution with an extra ground lead for more reliable electrical connections on a wide range of trailers and towing vehicles.