Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
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2004 Mini Cooper
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2004 Mini Cooper
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Wiring a trailer can be a headache if you have to splice into factory wires, but this harness avoids that completely. The Curt T-Connector plugs in line with the tail light connectors to give you a working 4-flat trailer plug. No cutting, soldering, or wire tracing—just plug it in and it’s ready to go.
The built-in powered converter keeps the vehicle’s wiring protected while sending the right signals to the trailer. It’s rated for 3 amps per circuit for stop and turn lights and 7.5 amps for tail lights, giving you plenty of power for typical trailer lighting setups without overloading the system.
If you ever need more than the standard 4-way setup, you’re set up for easy expansion. You can use a 4-to-5 adapter for reverse lights or step up to a full 7-way with an ETBC7 kit for trailer brakes and auxiliary power. It’s a straightforward way to future-proof your wiring without starting from scratch.
The harness includes a separate ground wire with a ring terminal, so you can attach it right where it belongs. That solid ground connection helps prevent weak signals or flickering lights, keeping everything working smoothly once it’s installed.
Customer Satisfaction Score:
97% were satisfied with this product
3% of customers were not satisfied
Ratings & Reviews
Ray S.
12/13/2017
It has been a year. The 4Runner tows intermittently. No problems with trailer lights since this unit has been installed.
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Mike L.
9/16/2025
It sounds like you have a bad ground connection. Find the grounding point where the trailer harness converter box grounds to the vehicle chassis. Make sure that connection is made to clear, bare metal. If it isn't, remove the ground screw and sand down a dime-sized area around the connection, down to bare metal. Install a star washer between the the ground lug's ring terminal and the vehicle chassis. This will ensure that the washer 'bites' into the metal and gets a good connection. Once installed, spray some spray paint over the connection to protect it. Rust Oleum works very well. Find the main ground connection on the trailer, which is usually on the trailer tongue. Give that connection site the same treatment as described above. You'll never have a problem again.