MECMO 4-Pin Trailer Wiring Harness for Subaru 2009–2024 — Vehicle-Side 4-Way Flat, Plug-and-Play

The MECMO 4-pin trailer wiring harness 56040 is a vehicle-side, plug-and-play 4-way flat connector built to add trailer tail, turn and brake light capability to compatible 2009–2024 Subaru models without cutting factory wiring.

If you tow a small trailer, cargo carrier or bike rack with a compatible Subaru Forester, Outback, Crosstrek, XV or Ascent that already has the factory tow package, this harness provides the factory-style electrical connection for trailer lights. It installs at the rear tail light junction using OEM-style connectors, includes a rubber dust cover for weather protection and uses heavy-duty wire with tin-plated copper terminals for corrosion resistance.

Which Subaru models and years is this harness compatible with?

This MECMO 4-pin harness is made for select Subarus equipped with the factory (OEM) tow package. It fits many model years but excludes specific hybrid or older sport variants listed by Subaru.

• Compatible with 2009–2024 Subaru Forester
• 2013–2024 Subaru Outback Wagon (excluding Hybrid)
• 2019–2024 Subaru Ascent
• 2016–2024 Subaru Crosstrek (excluding 10–12 Outback Sport)
• 2013–2015 Subaru XV Crosstrek (non-Hybrid)

How difficult is installation and will I need to cut vehicle wiring?

Installation is designed to be straightforward: the harness is a T-style plug-and-play unit that mates with the vehicle's existing trailer wiring at the rear tail light harness. No cutting, splicing, or special tools are required for supported models, keeping the factory wiring intact.

• Direct-fit vehicle-side 4-pin connector matches OEM sockets
• Plugs into factory tow-package harness located in the tail light area
• Removes cleanly if you later upgrade or replace the connector

What electrical and physical protections does the MECMO harness provide?

The harness is built to resist corrosion and environmental exposure so your trailer lights stay reliable. It uses bonded wiring and tin-plated copper terminals plus a snug rubber dust cover to keep moisture and dirt out of the connector.

• Heavy-duty bonded wire for mechanical strength
• Tin-plated copper terminals for better conductivity and corrosion resistance
• Rubber dust cover seals the vehicle-side socket from water and debris

What lights and signals will this 4-pin connector operate on my trailer?

The standard 4-way flat wiring carries the basic lighting circuits required for most small trailers: tail/running lights, left and right turn signals, plus brake lights. It does not carry 12V power or electric brake control circuits—those require separate adapters or a 7-pin arrangement.

• Powers trailer tail/running lights
• Supplies left/right turn signals and brake lights
• Does not include dedicated 12V accessory power or trailer brake control

Who this is for: Choose the MECMO 56040 harness if you own one of the listed Subaru models with the factory tow package and want an OEM-style, no-splice solution for connecting a small trailer’s lighting. It’s aimed at DIYers and installers who value a clean installation, corrosion-resistant terminals, and a weather-tight vehicle-side socket. If your vehicle lacks the OEM tow package or you need auxiliary power or electric-brake control, consider a different wiring kit or a 7-pin upgrade.