MECMO 4-Pin Trailer Wiring Harness for Toyota Pickup & Tacoma (1989–2004) — Plug-and-Play 4-Way Flat, Corrosion-Resistant

MECMO's 4-pin vehicle-side T-connector is a plug-and-play trailer wiring harness that powers tail lights, brake lights and turn signals for select 1989–1995 Toyota Pickup and 1996–2004 Toyota Tacoma models.

This vehicle-specific 4-way flat wiring harness (model 55379) is made to match the factory wiring locations on compatible Toyota Pickup and Tacoma rear tail light circuits so you can add trailer lighting without cutting or splicing factory wires. The kit includes heavy-duty bonded wire, tin-plated copper terminals for corrosion resistance, and a snug rubber dust cover to protect the vehicle-side socket when not in use. It’s intended for owners who need a simple, durable way to connect a trailer’s lighting system to their truck.

Will this wiring harness fit my Toyota Pickup or Tacoma?

Compatibility is limited to specific model years and vehicle-side wiring arrangements. This MECMO harness fits 1989–1995 Toyota Pickup (excluding some T100 variants) and 1996–2004 Toyota Tacoma (excluding the 1995 mid-year 5 models). Check your vehicle’s tail light connector location and compare with the product photos before purchase.

• Designed for vehicle-side rear tail light connector locations used on listed years
• Not compatible with certain T100 and mid-year 1995 Tacoma variants
• Fits factory wiring—no factory wire modification required

How easy is installation for a DIYer?

Installation is straightforward since this is a true plug-and-play T-connector: you plug the harness into the vehicle’s existing tail light sockets and route the 4-way flat lead to your trailer hitch. No cutting, splicing, or soldering of factory wires is necessary, reducing installation time and preserving factory wiring integrity.

• Plugs into factory tail light connectors located in the rear of the vehicle
• Includes pre-terminated connectors—no tools beyond basic trim panels and zip ties
• Recommended routing keeps harness clear of heat sources and moving parts

What features improve durability and weather resistance?

The harness uses heavy-duty bonded wire and tin-plated copper terminals for improved conductivity and corrosion resistance. MECMO supplies a tight-fitting rubber dust cover for the vehicle-side 4-way socket to help keep out water, dirt, and road debris when the trailer plug is not connected.

• Tin-plated copper terminals resist corrosion and maintain signal quality
• Bonded wiring improves abrasion resistance and long-term durability
• Rubber dust cover protects the socket from moisture and contaminants

What will this harness actually power on my trailer?

The 4-pin flat connector carries standard lighting circuits: tail/marker lights, left and right turn signals (combined with brake lights depending on trailer wiring), and a ground. It does not supply auxiliary power or electric trailer brakes.

• Tail and marker lights
• Left and right turn signals and brake lights (per standard 4-way wiring)
• Chassis ground return via the flat connector ground pin

Who is this for: MECMO’s 4-pin T-connector is for Toyota Pickup and Tacoma owners (see year exclusions) who want a no-fuss, factory-friendly trailer wiring solution. It suits DIY installers who prefer a plug-and-play approach, drivers who need reliable trailer lighting without modifying factory harnesses, and those who want corrosion-resistant terminals and a protected vehicle-side socket for long-term use.