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Hooking up trailer lights doesn’t have to mean cutting into your truck’s wiring. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs straight into the factory tail light connectors. Everything fits the way it should, no splicing or tracing wires required. Once installed, you’ve got a clean 4-flat connector ready for your trailer’s running lights, turn signals, and brake lights.
Bad grounds are one of the most common reasons trailer lights flicker or fail. This harness includes a white ground wire designed to attach directly to clean, bare metal on the frame. That solid connection keeps voltage consistent across all circuits so your turn and brake lights work every time. It’s a simple but critical fix for many of the electrical gremlins that show up when towing.
Some vehicles send out separate signals for stop and turn lights, which can confuse trailers that use a single wire for both. The Curt harness includes an integrated converter that combines those signals properly so your trailer lights work like they should. If you ever test it with a circuit tester, you’ll see full power on each of the four functions when everything is wired right.
If you plan to add a brake controller or upgrade to a 7-way setup later on, this harness gives you the foundation you need. Pair it with a 4-to-7-way adapter kit and you can easily add electric brakes or 12V power without redoing your wiring. It’s a plug-and-play starting point that makes future towing upgrades simple.
Customer Satisfaction Score:
99% were satisfied with this product
1% of customers were not satisfied
Ratings & Reviews
It was very simple to install. Instructions were very detailed.
High quality wiring harness
Works perfect!!! Fast shipping. Thank y ou.
Excellent service and product
Excellent quality. Loved the install video - really made it easy to get it up and running.
The wiring harness works great. Thanks!
went on easy and without a hitch (get it?) In all honest I ordered this and a hitch receiver and had it shipped to my house. I put the whole thing on the truck within about 40 minutes or so. Works well and was a simple installation.,
Great product and very easy to install. Very simple instructions that are easy to follow. There's no cutting or splicing involved it just plugs into vehicles existing harness.
I really didn't expect this harness to be so easy to install since nothing is ever this easy. It worked just like it should and would recommend it to anyone looking for a simple solution for trailer wiring.
The hitch came quickly and complete. I bought this hitch because it is an American made product. I was surprised how simple the installation was for one person to do. Thanks for making such a nice product.
This product worked as advertised and delivery was flawless and fast. These people know their business. Website is top notch!
Installation was so simple even a teacher could do it. Uhaul tried twice to hook up a trailer harness, neither time worked. Thanks to everyone at etrailer.com!
Very satisfied with the wiring harness. Everything went together good and works great. Get back with me in a few months and I’ll let you know if it’s still holding up because I will be using it frequently.
Got my trailer connector quickly and, as in past orders, done right done fast. I am completely satisfied. You guys should run the country!
The trailer light kit shipped quickly, installed in a few minutes, and works great. There was even an installation video to help me with the installation.
Just plain and simple. Does the job like it’s supposed to. Very easy. Thank you!
Fast shipping, easy to install.
very fast will order again
This was extremely easy to install in under 10 minutes works great & it all plugs together no cutting wires just drill 1 small hole for ground lug I put die electric grease in all connections & it was very affordable at only $xx.xx I got it shipped regular & was here in 5 or 6 days thanks e trailer for making a awesome product
this is my 3rd one in 15 years they really work well when there working there are a lot of reviews in trailer wireing about trailer rite side brake lite not working they say check ground if its a ground problem you would have trouble with other circuits please check the t-connector for power on both sides first the box shorts out not supplying power to all wires
The wiring was correct for the truck plugins but the 4-way flat connector doesn't fit in the housing on the tailgate so it just blows in the breeze. When calling customer service through Curt they want you to buy a bracket they make. This is the third harness I've used on this truck and all of the others fit perfectly in the tailgate housing. Wouldn't buy again for a perfect OEM fit.
Plug and play on my 2010 Canyon. Dropped the spare tire, opened tail light connector, plugged it in. Made a stud to ground to (clean, good grounds are very important). I found a perfect recess to “tuck” the module into. Add a wire tie, wal-la, trailer light harness.
Install was a breeze, worked flawlessly during the first tow. Appears to be a high quality product with good fit and finish. What more can I say... It is exactly what I needed and expected. I used a bit of extra wire loom I had laying around to add extra protection to the wires going to the plug, but beyond that everything was right there in the package thats needed to get up and running.
Alex H.
5/7/2015
No problems so far with a years use. Again can not stress how simple the install was. Hard to go wrong with their products.
(The Good)
The wiring harness is easy to install.
(The Bad)
The converter does not work properly on the trailer lights.
Brake & four way flasher lights work properly.
However parking lights don't come on. Also when the left or right turn signal is put on both of the trailer lights flash.
Truck is a 2005 Chevy Colorado Crew Cab Z71 without the 7-way connector
Mike L.
6/21/2019
For the parking lights, the first step would be to find if the problem is in the vehicle wiring or in the trailer wiring itself. Use a circuit tester on the pin of the trailer connector fed by the brown wire while the vehicles headlights are on. If the pin shows power, the wiring harness and converter is fine. If it does not show power, and the connections are fully seated in place, then the wiring harness is faulty and should be replaced. The issue with both turn signals firing at the same time is a classic manifestation of a ground problem. Make sure the trailers main ground connection on the trailer tongue is securely fastened and not loose or corroded. Make sure each trailer lamp is securely grounded to the trailer frame, and that each connection is not corroded. Ive linked you to a help article about troubleshooting trailer wiring, I hope youll find it helpful.
Helpful Links
Easy install, tested and worked as expe cted!
I recently moved to the Big Island of Hawaii where obtaining parts for vehicles has been very difficult. I have shy-ed away from utilizing the car dealers because their mark up on products are outrageous and turned to online shopping. I purchased a trailer and needed to replace the wiring harness on my truck in order to get my trailer street legal. I found the harness I needed on etrailer.com. The cost was very reasonable and they didn't charge me an arm and leg for shipping. Honestly I could have purchased two harness for the price the car dealership quoted me at. Normally when I purchase items online I receive it in 7 to 10 days. So when I got my box in THREE DAYS I was elated! I had no issues replacing the bad harness. All the electrical to the trailer WORKED! I wasted no time getting my trailer's safety inspection and registered so I can use it. Thank you ETRAILER!
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Marc
6/15/2021
Product works great, no issues