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Quickly and easily install a 4-way trailer connector on your vehicle with this custom harness. T-connector plugs directly into existing wiring. Required relays included.
Features:
Installation
This custom-fit T-One connector plugs into your vehicle's 12-pin wiring harness located behind the passenger's-side kick panel.
Once you've plugged in the 12-pin connector, plug the 4-way harness in beneath the vehicle, behind the driver's side rear bumper
Once installation is complete, the 4-way connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.
It is recommended that you use a small amount of grease on all electrical connections - the plug on your automobile and the 4-pole connector itself - to help prevent corrosion.
California residents: click here
All of the wires fell out of the gray connector on the Flat 4 wiring while routing the cable. No excessive pulling, they simply fell out upon minimal tension. Curt must have had someone new on the line that day as none of the wires were terminated/crimped properly. The relays worked great and I could use those. Etrailer Customer service has been just a hair above useless since wouldn't even acknowledge the time sensitive timeline I was on and they could not do any express shipping to assist with a replacement, the replacement proceeded to show up 2 days after the expected date, well after my timeline. I sourced the flat 4 harness from somewhere else, returned their replacement along with the defective flat 4 harness. I've requested a refund for the portion I had to source elsewhere via email and hand written note in the return box itself. I simply do not get any response or acknowledgement of the request. What was supposed to be a 30 minute install turned into an afternoon of customer service calls/emails, attempting to fix the harness, sourcing of a backup, anxiety if I'd get everything sorted in time for my trailering needs, revisiting the install with the backup since they couldn't support me with an expedited shipment, a return shipment of the unused replacement that arrived too late, and now I'm receiving "leave a review" emails pretty consistently, so here it is. A review. Faulty Harness and a customer service team that doesn't communicate well or have the ability resolve a time sensitive issue.
I'm thinking I will source my trailering items from somewhere else.
The job was exactly as instructions laid out. The customer service was excellent and the items arrived on time.
I have not installed this item yet, but I am sure it is fine. I had ordered this trailer wiring harness from a different seller. After 11 days waiting I cancelled the order and ordered from etrailer on a Monday. It arrived ahead of schedule on Wednesday and was exactly what I ordered, complete, and in good condition. I can't ask for more than that.
Installed trailer wiring harness and passenger side window and door locks won't work. Got 2 relays with wiring but there is a third brown plug with not connector/relay. Install instructions are so poor and lacking info that I am not sure if there is supposed to be another relay.
Kate F.
5/6/2026
Thanks for your feedback Ike. That definitely sounds frustrating. For the Curt 56225, there should only be two relays included, so you’re not missing a third. The extra brown connector you’re seeing is typically a factory plug on the vehicle that doesn’t get used for this installation. Issues with door locks or windows usually point to a relay not being fully seated or a connector not quite lined up, especially on the passenger side. It’s worth double checking those connections and making sure everything is firmly clicked into place. After you check the connections, please let me know it that does the trick. We also hear you on the instructions. They can be a bit light on detail, and we appreciate you calling that out.
Super easy install! Does the intended job, thanks etrailer!
This kit has exactly what my 2015 frontier needed. The pieces are good quality and everything for exactly as it should. The instructions were accurate and I was able to install everything, but some steps were a little vague and a couple of additional pics would have made them more clear. Additionally, a mounting bracket for the trailer connector would be a great addition.
The install was very simple - I did not have any issues- and the product performed exactly as expected.
Everything came as planned. The wiring harness worked perfect. The video made it very simple.
Wiring harness fit my Nissan Xterra perfectly. Took about 15 minutes to hook everything up and the trailer lights all work as expected. Very happy with the harness, relays, and trailer connector.
great product and great prices
I received my hitch and wiring harness kit for my 2019 Frontier within a few days after ordering. The items were well packaged, and nothing was damaged. The install instructions/video on your website were spot on. I had the whole thing installed and ready to go in less than an hour. Fit and finish of the etrailer hitch is very nice for the price. I would definitely recommend etrailer.com to others.
Easy installation... the online videos really helped.
I had an existing harness that was installed with the hitch and the running lights were not working and the shop couldn't figure out the problem!
I removed the passenger side panel and saw the relays were missing. I decided to just tackle the fix myself and it worked out great.
Great product! Wish I'd bought this first.
I wasted alot of time trying to get running lights on my Nissan Xterra pigtail. I had brake and turn signal only. Excellent customer service- Molly solved problem with this harness. Best of all - she saved me over $200.00 that Nissan wanted just to diagnose problem. If I can install this, anyone can. It only took 10 minutes and I had running lights.
Thank you
Very simple install, plug and play electrical connections, very simple to use and very good quality product. Very happy it was put on in PA on Friday afternoon and hauled a uhal trailer to GA Saturday morning. Had 0 issues. Definitely a 5 star rating
This was not listed as an exact fit but worked perfect with my 2024 Nissan Frontier. It all plugged into the factory wiring. Made for a very easy instillation.
Great service and very helpful videos as well. Thank you
Right part for the right car. Order shipped the day I placed it, arrived earlier than scheduled. Combined with their numerous videos on installation, hard to think of a better service package out there. So easy, so simple. And for less than half what my local parts shop quoted (and didn’t have in stock)
I’ve got three emails confirming order, shipment and delivery.
I’ll be back when it’s time to wire up the Rogue.
Connects perfectly with the stock wiring. Looks factory. Good product to have if your Xterra didn’t come with a tow package
Raleigh
3/29/2025
Been good after a year. Still works as expected!
Everything was on time and fit like a glove. Easy tracking shipment. Well done etrailer
This wiring harness plugged in and the install only took about 15 minuites start to finish. It worked great!
provided everything I needed and more. It was securely packaged and in mint condition. I will be able to tow my trailer legally when it's dark.
Vince
12/15/2024
Exceptional. No problems at all.
I purchased a wiring kit and hitch ball for my new 2016 Nissan Frontier. The truck does not have the factory tow package. However, it does have a class-II tow bumper and Nissan sends them all pre-wired for lighting, but not activated.
The kit I ordered from etrailer had everything I needed to activate the factory wiring harness (a couple of simple, plug-in relays) and a 4-pin flat plug that also just plugged into the factory pigtail at the rear of the truck. Added a bracket for the flat plug (also from etrailer) and in about 30 minutes I was good to go.
I consider myself above average in the shade-tree mechanic stuff, but I think pretty much anyone could do this installation. It was simple and straightforward. They even have a very helpful video of the install procedure online.
Based upon this purchase, I would consider etrailer for any future purchases I may have for trailering products and their shipping was fast and well packaged too.
T. R.
12/13/2017
Perfect with no issues whatsoever. Id buy it again.
I purchased the Curt trailer hitch and wiring harness for my recently purchased 2015 Xterra. Plan on towing 3000# max utility trailer. Shipment arrived very quickly after placing order, well protected in box. Install was a breeze. Took more time rounding up the tools than installing the hitch and harness. Did not need to drop the exhaust to install hitch. Nissan installed bolts are VERY tight - required 24" breaker bar to loosen. Called about harness installation. On hold less than a minute, great response. Hooked up to trailer and all lights worked. Highly recommend these products.
Rob L.
8/12/2016
Dont use it much but when I do it functions well.
This was easy, clear instructions, simple procedure
Curt Ball Mount for 2'' Hitches-C45030
Curt T Connector Vehicle Wiring Harness w/ 4 pole flat trailer connector-C56225
Curt Trailer Hitch Receiver Class 3 2''-13241
Website easy to use. PayPal available (the main factor).
Fast shipping. Well packaged. All 3 items installed within minutes.
Amazing experience with etrailer!!
Will definitely return to do business.
Thanks!!
60 F.
10/27/2017
We are more than pleased with your products and the transaction. Thanks again!
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Mike L.
4/4/2026
Thanks Tim, I'm glad we could help!