Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
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2009 Toyota Tundra
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2009 Toyota Tundra
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Wiring a trailer setup doesn’t have to involve cutting or guessing. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs right into existing light wiring to give you a clean 4-flat output. The plug-in design keeps installation simple—just connect it behind the tail lights and you’re ready for running, turn, and brake lights without splicing any factory wires.
Many vehicles can’t handle the added load from trailer lights on their own circuits. This harness includes a powered converter that draws power directly from the battery through its included power lead. That setup takes the electrical load off your vehicle’s lighting system and prevents trailer shorts from damaging the original wiring.
The Curt C56434 requires a dedicated 12-volt feed from the battery for proper function. Running this power wire straight to the positive terminal gives the converter stable voltage and ensures built-in circuit protection works as designed. That’s what makes your trailer lights bright, consistent, and safe every time you tow.
This kit is designed with hidden connectors that tuck behind interior panels and trim for a factory-style look. The 4-flat plug can be stored inside the cargo area when not in use or mounted outside near the hitch with optional brackets. It’s neat, protected, and ready when you need it.
Once installed, you get a standard 4-pole flat connector that powers your trailer’s running, turn, and brake lights or other lighting accessories. It’s exactly what you need for basic towing setups or for converting later to a 7-way if you decide to add brakes or charging circuits down the road.
Customer Satisfaction Score:
98% were satisfied with this product
2% of customers were not satisfied
Ratings & Reviews
Kate F.
3/18/2026
I looked at both the wiring harnesses that you have purchased from us and both are a standard 4 flat, now I am not saying you are wrong because sometimes things get out of factories not made correctly. Can you please respond directly to the email you receive with pictures of the new 4 flat, the 4 flat on your trailer, and a picture of them not working? I would like to figure out what is going on with this Matthew =)
Mike
4/17/2025
Love it, well in fact I never have to think about it but I use it every week to take the trailer to the dump for grass clippings. The wiring kit has never had an issue, all lights work, still just as happy!
William
10/14/2020
still working good
Kate F.
10/8/2025
Glad we had the right fit for you H.A.V.! What are you towing with your new wiring?
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Heather A.
5/26/2026
We really appreciate you taking the time to write this especially since you don’t normally leave reviews! Saving money and getting it installed yourself is a huge win, and we’re glad the resources gave you the confidence to tackle it without any major hassle. That’s exactly what we hope for with the step-by-step videos and support. Side note, are you towing a trailer?