Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
This item does not fit your vehicle
2012 Ford Explorer
These items fit your vehicle
2012 Ford Explorer
To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.
Wiring a trailer doesn’t have to mean splicing or chasing down circuits. The Curt T-Connector Vehicle Wiring Harness with 4-Pole Flat Trailer Connector plugs into factory tail light wiring on the driver side, giving you a simple, direct connection. The lengths are configured to match the vehicle layout, so everything lines up where it should. It’s a straightforward install designed for vehicles without a tow package.
This harness includes a powered converter that isolates the trailer wiring from the vehicle system. That setup helps prevent shorts and overdraw issues that can blow fuses or damage sensitive electronics. The converter supports up to 7.5 amps current for the running light circuit, enough for standard trailer lights while keeping your vehicle wiring protected.
You can keep the 4-flat connector stored inside the cargo area or route it outside near the bumper through an existing floor grommet. Both methods keep wiring neat and out of harm’s way. If you prefer an exterior mount, brackets like part #18140 and #18144 secure the connector cleanly without drilling into metal.
The Curt harness uses Surface-Mount Technology, which improves durability and current handling compared to older through-hole circuit boards. It reduces electrical resistance and heat build-up, so your trailer lights stay bright and consistent mile after mile—even when towing in hot weather or on long trips.
Customer Satisfaction Score:
100% were satisfied with this product
0% of customers were not satisfied
Ratings & Reviews
perfect and video makes instillation a snap
Knowledgeable staff, fast delivery, item as described and appears to be of good quality.
Very Happy with this product still works well.
No problems found at all. Works as exp ected.
Very simple to install, plugged right in. 1 year after installing everything still works perfectly.
After a year, lights still work perfectly. Easy to install. Great experience finding the item I needed and getting it fast.
electricity made easy
Fast free shipping. Items arrived on time and are exactly as ordered.
we could not figure how to install so we used one of the suggested people to install and we are very pleased
good product. works as advertised. I used this on 2018 ram promaster city wagon. running the wire's wasn't easy but I did it , if I had to do it again I could do it faster than 5 hours knowing how to disassemble panels/headliner and route wire.
The harness is great and the installation is a little tough but doable for someone handy. I would say that it’s hard to feed under the van without it being lifted.
2nd order from them. Fast shipping and correct parts both times. Simple install, doesn’t effect vehicle lights at all.
Product fit perfectly per the installation instructions.
The hitch and wiring were custom made and the video instructions were clear and helpful.
Great fit….. works great !!!!
It's great to have the correct wiring kit for your particular vehicle. No cheap crimp on connectors, no guessing which wire to tap into. Works correctly first time, every time. It was, however, VERY challenging to run the power wire safely, and properly from the front to the back and the kit din't provide a suggested route.
Very helpful great customer service thanks Brittany
I purchased this for use on a 2020 Ram Pro Master City Wagon. Although the installation is not difficult, it is rather involved. Reading the directions and also watching the online video atthetrailer.com was extremely helpful. You need to fish the wires down to each taillight. Are used a simple coat hanger for this. You also need to drop the headliner in order to transverse from one side to the other. All in all, it probably took me two hours from start to finish. Everything was plug and play and it works as expected.
the Curt T-one vehicle wiring harness with 4 pole flat connector. The first one i received was defective through no fault of etrailer, and Allison did what was necessary to arrange the shipment of a replacement on a Sunday. This is not the easiest installation in the world. It's a little difficult to snake the wiring down to the tail lights, but very doable. I think however etrailer's video of this installation is somewhat misguided. Although I have the equipment to jack the van up and run the power wire underneath the van, it is ridiculous to do so. I found it much easier and faster to run the wire inside the van. This is done easily by removing the little black storage compartment above the left wheel well, (you need not even remove it all the way, just pull it out at the top,) run the wire behind it, then removing the left sliding door sill plate and zip tying the power wire to an existing harness underneath it, then removing the driver's door sill plate and zip tying the power wire to the existing harness there, then around and up under the dash, then poking a hole for the wire thru an unused feed-thru plastic plug on the firewall behind and below the battery. Very fast and easy.
You should redo your video.
For 2019 Ram Promaster City this wiring harness has everything that you need and has pretty good instructions. You need a fish wire to install this and I just used the black power line and was very gentle. lol.
This is 4 stars and not 5 because the lengths of the wires that they give you are JUST long enough to do this. It would have made install easier if you had an extra 6-12 inches in some cases. Over all simple install but not "easy."
Joseph
3/4/2021
still working fine after one year with no issues and probably monthly use.
The components looks to be assembled well. I take possession of the vehicle in 2 days but can't install till mid week due to weather
Dodge Promaster City, wiring harness for trailer hitch: The product works great. However, as noted on the website, this installation is tricky. As a matter of fact, it's a pain in the rear... If you have a work van version of the City, it would be a lot easier. I have a trimmed out 5 seater, though. The ceiling tray needs to be dropped and trim opened up on the rear drivers side in the storage area. I would recommend pulling your power from the 12 v cigarette lighter in this location, the fuse is plenty big for the lights and it's not that likely you'd be using both simultaneously. Installation instructions could be better, though. I agree with the assessment that this is an expert type install. If you've messed around with this stuff and can fish wires ( a coat hanger works well), shouldn't be that bad. An extra set of hands is really helpful, though.
Laura E.
9/19/2017
We strongly recommend running the 12 volt power wire from this wiring harness directly to the vehicle battery. The 12 volt accessory circuit was not designed to support the additional load of a trailer wiring harness. A wiring harness must have its own dedicated circuit directly to the battery. We have seen many instances where customers have tapped into a 12 volt accessory circuit, like a car lighter socket, and the harness failed. We have also seen instances where the accessory circuit on the car failed in addition to the trailer wiring harness. Also, this will typically void warranties both with the wiring harness and on the vehicle. We understand that running the 12 volt power wire can be a more time consuming task, so we wrote a help article on tips for running this power wire, which may be found at this link. Be sure to avoid any moving components such as suspension or steering. You will also want to avoid any areas that get excessively hot. Again, thank you for your business and we look forward to doing business with you in the future.
Helpful Links
Wow!!!! Fast shipping. Product was new and in mint condition. Will be ordering more
Wiring harness functions as promised. Anyone who's reasonably handy can install it with the video.
From ordering to delivery the process was flawless , product came early , I watched the installation video which was helpfull made the installation process easy
Do you have a question about this Custom Fit Vehicle Wiring?
Info for this part was:
At etrailer we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Brooke M.
1/13/2025
Thanks for saying so, Steve. Brittany will love to see this! Ill be sure to show it to her. :)