Connect your trailer's running lights, brake lights, and turn signals to your tow vehicle in minutes -- no wire cutting, no splicing, no guesswork. The CURT 56016 T-One connector uses a plug-in design that taps directly into your vehicle's existing tail light wiring harness, delivering a clean, reliable 4-flat output at the hitch end. Whether you are towing a utility trailer, a popup camper, a small travel trailer, or a boat, this harness gives you a proper, code-compliant light connection every time you hitch up.
The CURT T-One series is one of the most widely used vehicle-specific trailer wiring solutions in the aftermarket. The 56016 is a vehicle-specific fitment, meaning CURT engineered the connector plug shapes and harness routing to match exactly one or more production vehicles without any cutting or circuit tapping. You unplug the existing tail light connectors, plug the T-One in-line, and route the 4-flat pigtail to your hitch receiver area.
The result is a factory-quality integration that protects your vehicle's electrical system. A built-in converter module manages any differences between the tow vehicle's combined or separate turn/brake light signals and the trailer's 4-flat wiring standard, so your trailer lights work correctly regardless of how your vehicle's tail lights are wired internally.
Plugs directly into OEM tail light connectors. No wire cutting or soldering. Uninstalls just as easily if needed.
Standard 4-pin flat connector output is compatible with the vast majority of utility trailers, boat trailers, and small campers on the market.
Harness plugs and routing engineered for a specific vehicle application -- no universal adapter fumbling or mismatched connectors.
CURT T-One connectors are injection-molded, weather-resistant housings with corrosion-resistant terminals rated for outdoor towing use.
When you tow a trailer, federal law requires your trailer's brake lights, turn signals, and running lights to function. A T-connector (also called a T-one connector or tow harness) bridges your vehicle's existing lighting system to the trailer's 4-flat plug. Without one, you would need to splice directly into your tail light wiring -- a modification that can void warranties and create electrical gremlins.
The CURT T-One approach eliminates that risk. The harness is purely plug-in: the factory tail light connectors unplug from the vehicle loom, the T-One inserts in between, and the 4-flat pigtail is routed to your bumper or hitch area. If you sell the vehicle or simply want to remove the harness, you unplug everything and the vehicle wiring returns to stock condition.
Many modern vehicles use a combined brake and turn signal wire at the rear (a single wire that handles both functions). Most trailers use a separate-function 4-flat system (dedicated wires for left turn/brake, right turn/brake, running lights, and ground). The T-One module converts between these two systems automatically, so your trailer lights operate correctly whether your vehicle uses a combined or separate system.
The output of this harness is a standard 4-pin flat (4-flat) connector, the most common trailer light plug style in North America. It is compatible with:
If your trailer uses a 5-flat, 6-round, or 7-way RV blade connector, a separate adapter is required and is not included with this harness.
Most installers complete the T-One harness in 15 to 30 minutes with no special tools. General steps:
CURT Manufacturing is one of the largest hitch and towing accessory brands in North America, and the T-One series covers thousands of vehicle applications from compact cars to full-size SUVs and trucks. The 56016 is a vehicle-specific SKU in that catalog -- the exact vehicles it fits should be confirmed via CURT's vehicle fitment guide using your year, make, and model. CURT part numbers in the 56000 range are typically matched to specific import and domestic passenger vehicles commonly used for light-duty towing.