Nilight 4-Pin Trailer Wiring Harness

If you only need your vehicle to send basic lighting signals to a trailer, a vehicle-specific plug-in harness is a simpler fit than wiring that requires cutting into factory wires. The Nilight 4-pin trailer wiring harness connects to existing vehicle wiring and provides a 4-flat connector near the hitch. Its listed fitment covers 2020–2021 Lexus RX350 and RX350L models without a factory tow package, plus 2008–2019 Toyota Highlander models. Match your vehicle to those details before choosing it, the Lexus fitment is limited to vehicles without the factory tow package.

Where it shines

The main benefit is a direct connection to the vehicle’s factory wiring, with no cutting or splicing described for installation. The harness plugs into wiring located beneath the rear floor panel and leaves the 4-flat connector stowed near the trailer hitch. That can make setup more straightforward when you need trailer tail lights, brake signals, and turn signals, rather than a more involved wiring setup.

Picture connecting a small trailer before a weekend trip: the rear 4-flat plug is there to connect the trailer’s lighting, and the included rubber dust cover fits over the connector when it is not in use. On the spec sheet, this is a trailer-lighting harness, not a complete description of every towing function a vehicle or trailer might need. If you need features beyond the listed lighting connections, this kit’s details don’t establish that it provides them.

Quick overview

The kit includes a custom 4-pin trailer wiring harness, nine zip ties, a 10A fuse, and a screw. Its 4-flat connector is a common style for trailer lighting, and the stated functions are tail lights, brake signals, and turn signals. The included fuse and fasteners are part of the package, but the description does not specify installation time or additional tools, so don’t assume the job is identical across all listed vehicles.

Worth considering if your vehicle matches the stated fitment and you want a plug-in route to basic trailer lights. If you prioritize a simple connection without altering factory wires, this approach may suit you better than a harness installation that calls for cutting or splicing. Fitment is the important trade-off: the listed Lexus models must be without a factory tow package, while the Highlander years are specified separately.

Best use cases

This harness is aimed at connecting compatible vehicles to a trailer’s standard 4-flat lighting plug. It makes sense for drivers who need the basic rear lighting signals identified in the product details and want the connector kept close to the hitch when parked. The dust cover helps shield the unused plug from outdoor elements, though the description does not provide a separate maintenance schedule or a specific durability rating.

It’s not for you if your vehicle falls outside the stated year and model range, or if you need towing functions beyond tail, brake, and turn-signal lighting. A more extensive wiring solution may be the better direction for requirements this kit does not describe.

Should you buy it?

Choose the Nilight harness when the vehicle fitment matches exactly and your goal is a plug-in 4-flat connection for trailer lights. The no-cut, no-splice setup and included dust cover address two practical concerns: connecting to existing wiring and protecting the loose connector when it is stored. Skip it if you have a factory-tow-package Lexus covered by a different setup, a vehicle outside the listed years, or needs that go beyond the three lighting functions named here. Those checks matter more than the promise of an easy installation.