Tekonsha 118304 T-One 4-Way Flat Harness w/Converter
Tekonsha 118304 T-One 4-Way Flat Harness w/Converter — Product description
The Tekonsha 118304 is a T-One T-Connector harness that gives your 2004-2010 Toyota Sienna a clean 4-way flat trailer connector. It plugs straight into the factory wiring behind the taillight, no cutting or splicing, and the built-in converter with circuit protection keeps the van's electronics safe while it powers the trailer lights.
If you tow with a 2004-2010 Toyota Sienna, this is about the easiest wiring job you'll ever do. The Tekonsha 118304 T-One T-Connector is a custom-fit harness, built to match the factory wiring on that generation of Sienna. No test light, no splicing, no scotch-locks. You find the plug behind the taillight, unplug it, and drop the T-Connector inline. Ten minutes, maybe less if you've done one before.
Here's what makes the T-One design nice. Instead of tapping into your van's wiring and hoping the connection holds up, it uses the plug-and-play connectors that are already there. That means a solid, weatherproof link that isn't going to corrode or work loose the first time you hit a bump. The 4-way flat plug on the output is the standard connector for small trailers, so it'll match most utility trailers, small boat trailers, and pop-up campers right out of the gate.
The built-in converter is the part that matters if you care about your electronics. A lot of newer vehicles run separate turn and brake signals, and wiring a trailer straight into that can back-feed and confuse the van's computer. This harness runs a powered converter that pulls current from the battery instead of the taillight circuit, and the circuit protector guards against shorts and overloads if a trailer plug gets wet or a bulb fails. Your Sienna's factory lighting stays isolated and safe.
It comes with the 4-flat plug and a dust cap to keep the contacts clean when you're not towing. The wire is a bonded run that tucks up out of the way. This is a Tow Ready assembly from Tekonsha, the same folks who build the brake controllers and towing electronics that hold up season after season. If you're adding a hitch to a Sienna and need lights on the trailer, this is the connector that gets you there without a wiring headache.
Key Features
- T-One custom-fit T-Connector for the 2004-2010 Toyota Sienna, matched to the factory harness for a plug-in install with no cutting or splicing.
- 4-way flat output connector, the standard plug for small utility, boat, and pop-up camper trailers.
- Built-in powered converter pulls from the battery so the van's separate turn and brake signals reach the trailer correctly.
- Circuit protector guards against shorts and overloads from a wet plug or failed bulb, keeping the Sienna's factory lighting isolated.
- Weatherproof plug-and-play connectors resist corrosion and stay put over rough roads.
- Includes the 4-flat plug and a dust cap to keep the contacts clean between tows.
Why Buy from NVN Marine
- Authorized Tekonsha reseller, full manufacturer warranty
- NMEA member and ABYC certified, advice from real boat techs
- Same-day shipping before 3 PM ET on in-stock items
- NY headquarters and Fort Lauderdale flagship retail store
Technical specifications
| Title | 4-Way Flat Replacement for OEM Wiring Harness with Circuit Protector Converter |
|---|---|
| Brand | Tekonsha |
| Manufacturer Part Number | 118304 |
| UPC | 016118057966 |
| Product Line | T-One |
| Series | Tow Ready |
| Trailer Connector | 4-Way Flat |
| Converter | Circuit Protector Converter, built-in |
| Installation | Plug-in replacement for OEM wiring harness |
| Vehicle Application | 2004-2010 Toyota Sienna |
Frequently asked questions
What vehicle does the Tekonsha 118304 fit?
It's a custom-fit T-One harness for the 2004-2010 Toyota Sienna. The connectors are matched to that van's factory wiring, so it plugs straight in behind the taillight.
Do I need to cut or splice any wires?
No. The T-One design uses the plug-and-play connectors already in your Sienna. You unplug the factory connection, insert the T-Connector inline, and you're done. No test light or splicing needed.
What does the converter do?
The Sienna runs separate turn and brake signals. The built-in converter pulls power from the battery and combines those signals into the standard 4-way flat output, so the trailer lights work right without back-feeding the van's electronics.
What size trailer connector does it use?
A 4-way flat, the most common connector on small trailers. It handles running lights, brake lights, and turn signals for utility trailers, small boat trailers, and pop-up campers.
Does the circuit protector do anything I'll notice?
It works in the background. If a trailer plug gets wet and shorts, or a bulb fails, the protector keeps the fault from reaching the Sienna's factory lighting. You just won't blow a fuse in the van.
Is there anything to keep the plug clean when I'm not towing?
Yes, it comes with a dust cap that snaps over the 4-flat plug to keep dirt and moisture off the contacts between trips.
