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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. Powered Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

Item # 118585
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Custom Fit Vehicle Wiring

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118585 - Powered Converter Tekonsha Trailer Hitch Wiring
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system. 1-636-306-4830 to order Tekonsha custom fit vehicle wiring part number 118585 or order online at Free expert support on all Tekonsha products. Guaranteed Lowest Price and Fastest Shipping for T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector. Custom Fit Vehicle Wiring reviews from real customers.
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  • Reviews (46)
  • Q & A (0)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118585

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • Powered Converter
  • Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Run hot lead to car battery
  • Includes ModuLite to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects directly to battery to avoid overloading vehicle's electrical system
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 4.2 amps per circuit
    • Tail lights: 7.5 amps per circuit
  • 1-Year limited warranty


This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located behind the driver's-side and passenger's-side tail lights. You will have to remove the tail light assemblies to access this harness.

T-One Connection Location Points Behind Tail Lights

Once you've plugged in the T-connector, run the hot lead up to your car battery. Connect the lead to the included fuse holder, and then connect the fuse holder to the positive terminal on your battery and insert the provided fuse.

Once installation is complete, the 4-way connector will be stowed within the jack storage compartment of your cargo area.

It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.

ModuLite Powered Tail Light Converter

A ModuLite power module is built into this T-One connector. Because most trailers run on a two-wire system - wherein the brake and turn signals are carried on one wire - the separate brake and turn signals from your vehicle's three-wire system need to be combined so they are compatible with the wiring system of your trailer. This power module functions as a tail light converter to combine the brake and turn signal functions of your automobile so that they run on one wire to properly activate your trailer's tail lights. Note: This will not affect how the tail lights on your vehicle operate.

With a ModuLite, your trailer's lights will be powered without overloading your vehicle's electrical system. Because the module draws power directly from your car's battery and bypasses the electrical routes that are used by a basic wiring harness, there is virtually no draw on your tail light circuits.

118585 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118585 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118585

Average Customer Rating:  4.8 out of 5 stars   (46 Customer Reviews)

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring. Powered ModuLite reduces strain on wiring system.


Everything on this wiring harness fit perfectly. Installation was foolproof with etrailer video instructions.


Hello. I have yet to install the wiring harness, because it shorted out my fuse after the initial installation. I did not run the wire from the battery, wich seems like a major pain for a modern vehicle.

Your vehicle shorted because the wiring harness was not run to the battery. The power wire is required on trailer wiring harnesses for some vehicles because the electrical system on those vehicles cannot handle the amperage draw associated with trailer lights. The power converters and ModuLites used in these applications protect the vehicles sensitive electrical system.
-- Etrailer Expert Sierra K - 08/13/2021

Ford Transit Connect

This was the perfect wire harness for the Transit Connect 2012
The passenger side wire harness should be 6 inches longer to allow ease of connection and reach just below the bumper. It is tight to get your hand up inside the bumper to make the connection.


Product shipped quickly and e-trailer agent James sent instructions on the install. EZ PZ. Thank you James. Everything works spot on.

Ford Transit Connect

The hitch is great, never had any issues after installing it. Shipment was ok. Lost a ton of parts during transit and needed a replacement which they did in a timely manner. Would for sure recommend this company


This is an awesome wiring harness, well thought out. The directions were very clear and everything I needed was included. Whoever put this together had actually installed one before. The directions gave me tips so I wouldn't back myself into a corner. I would highly recommend this to anyone!


Box ripped opened, Harness Missing. Sent E Mail reply but no answer

Customer service will reach out to you.
-- Etrailer Expert Thomas M - 12/21/2021


the hitch mounted very easy, with no problems. the wireing harness was put togeather in a complete packet, and very simple to enstall. we was able to put the small black box into the left rear light houseing for total wether protection, and spliced the two wires over to the right rear light housing unit. when finished, it looked very professional done. not so much on our part, but the quality of the products that you supplied sorry about not having any pics, they did,nt come out very good


Works great. It was pretty easy to install once I got the mounts on my vehicle tapped (they were a little gunky and needed help taking the bolts). I am no mechanic and, although I had help tapping the holes, I did the rest of the install myself, I mean all by myself. It was totally easy as a one person install and took me only maybe an hour to mount the hitch receiver and wire up the trailer lights connection.

2013 Ford Transit Connect

The trailer wiring harness for my 2013 transit connect was one of the more difficult hookups I have done. The most difficult step for me was running the power feed wire from the rear of the vehicle to the battery in the front. The harness it self was as advertised and plug and play. Most of the time consuming work was because of vehicle design not because of harness design. The instillation video was a life saver. shipping was quick and the product worked as advertised.


This product worked really well. Easy to install and the installation video from etrailer was very helpful.

2012 Ford Transit Connect

I am very happy with the wiring harness I purchased last year ! It has worked flawlessly and made my Transit connect a much more versatile vehicle ! Thank you for the follow up !

2013 Ford Transit Connect

Excellent product


Great product arrived on time..easy directions
(Watch video)
I used a straightened wire hanger to run black wire to battery from hitch location.
It made it a lot easier to run along and through the frame and up into the engine compartment saving time and scratched knuckles...
(Note) It is not necessary to remove threaded bolts from back of the tail lights after removing the black nylon fastners from inside.
Thanx again etrailor team for making products any back yard shade tree guy can install.
I'll tell everyone what a great company you are...

Ford Transit Connect

Ordering the electrical harness was a good idea to go along with the etrailer hitch for my '11 Ford Transit Connect. If the green/red wire could be around 6-8" longer, it would then be easier to connect them on the rear passenger side bumper area. Other than that, very convenient.


The hitch installed easily, all holes were in exactly the right place. There is plenty of clearance around the exhaust. No rattles or vibrations from the installation. The hitch is capable of much more than the van is. I use it to pull a small sailboat.

2010 Ford Transit Connect

Great product, easy to follow up installation instructions. Even a carpenter can do it!!
Best way to power the system is around the car threshold under the covers.
I don't believe a pro installer can do it better, very good product!!
Cornel the carpenter


Ordered mutiple hitches and wiring harnesses. All came quickly and installed without issue. Great service and pricing!


Ordering was easy, package arrived on the day promised, product was right on the money and went on beautifully! Saved us about $300! We pulled a uhaul trailer from N. Ga to Central Florida on our new hitch and it was perfect! Thanks so much!


ready made kit and fits great


Arrive on time exactly what I ordered

2013 Ford Transit Connect

The harness works great! Easy to install, well documented.


Mathew took my call and it was all easy. The hitch arrived 5 days later and everything looks top notch.


Great shipping time! Was fairly easy to install, even for an old guy with a bad back.


Very easy to install and easy to remove if need be.

Show More Reviews

See what our Experts say about this Tekonsha Custom Fit Vehicle Wiring

  • Will the T-One Vehicle Wiring Harness Work On 2010 Ford Transit Connect With Reverse Sensors
    The T-One Vehicle Wiring Harness part # 118585 is a great option for a 2010 Ford Transit Connect and what I recommend using. It does not contain any sort of feature to disable the reverse safety system (RSS) but it will work on models with reverse sensors. This may be an issue while towing with a trailer connected. I wouldn't be able to say for sure so looking in your owner's manual or reaching out to the dealer would be the best option.
    view full answer...
  • Recommended Trailer Wiring Harness Option for a 2013 Ford Transit Connect
    The only available plug-in-play trailer wiring harness option for a 2013 Ford Transit Connect is currently the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118585. This is an excellent option that provides a standard 4-way flat trailer connector which is most common. It does not require any splicing into the vehicle.
    view full answer...
  • Trailer Wiring Harness Options for a 2010 Ford Transit Connect
    The Curt trailer wiring harness, # 56090, is a fit for a 2010 Ford Transit Connect. I have included a link to the installation instructions for you. If the vehicle came with a factory tow package, the correct wiring harness is # 118585. I have included a link to the installation instructions for this harness as well.
    view full answer...
  • Comparing the Curt T-Connector 56090 and Tekonsha T-One 118585 for a 2010 Ford Transit Connect
    The Curt T-Connector Vehicle Wiring Harness part # 56090 and the Tekonsha T-One Vehicle Wiring Harness part # 118585 are both fits for your 2010 Ford Transit Connect. They are essentially two different manufactures version of the same product. The purpose is the same as well as the install. The only difference is really in terms of quality and that edge goes to Tekonsha as we have less issues with the T-One than we do with the T-Connector but both will work just fine for you. I have attached...
    view full answer...
  • Trailer Wiring harness # 118585 Has Constant Power All the Time
    T-One Vehicle Wiring Harness # 118585 will always have constant power running to it because it is a powered harness connected to the vehicle battery. The only time this is an issue is if a trailer has LED lights. Bleedover from the 12 volt circuit that powers the harness can dimly light up LED lights on a trailer if the trailer is left plugged in. In order to get the unit to shut off when you turn the vehicle off you could install a battery isolation solenoid, # TR118665. The wiring harness...
    view full answer...
  • Does Curt 1-1/4 Inch Trailer Hitch Receiver C12076 Include the Ball Mount
    No, the Curt Class II hitch receiver # C12076 does not include a ball mount, hitch pin or clip. You will need to add a hitch ball of appropriate size to match your trailer and a pin and clip # F-4. I have included a link to our page for Class II hitch balls with the required 3/4-inch shank diameter (to match the supplied ball mount which has a 3/4-inch ball hole). With this link you can select a Class II hitch ball of the appropriate size to match your trailer coupler, either 1-7/8 inch...
    view full answer...
  • Recommended 4-way and 7-way Trailer Connector For 2011 Ford Transit Connect
    If you have no trailer connector on your 2011 Transit Connect, the first thing you will need is a 4-way connector. I recommend the T-One Vehicle Wiring Harness, part # 118585. This plugs into the vehicle wiring located behind the tail lights. You just plug this harness into the tail light wiring, then run the hot lead wire to the positive battery cable. Then to install a 7-way and 4-way trailer connector you will need part # ETBC7. This plugs into the 4-way connector. If you are installing...
    view full answer...
    Image 1 for
  • Parts Needed to Tow a Trailer with a 2010 Ford Transit Connect XLT
    We definitely have parts you can use so that you can tow a trailer with your 2010 Ford Transit Connect XLT, however since the owner's manual states that Ford does not advise towing with your vehicle I don't really have a way to verify a safe towing capacity so you'll need to reach out to your local Ford dealer or just understand that you'll be flying blind when it comes to safe towing weight ratings. If you decide that you still want to tow with your Transit Connect then I recommend installing...
    view full answer...
  • Difference Between Trailer Hitch Receivers That Fit 2013 Ford Transit Connnect
    The only difference between the the 2" hitches that fit your 2013 Ford Transit Connect is, in fact, the installation that you mentioned. There is no downside whatsoever to the the easier-to-install unit, which is the Draw-Tite Trailer Hitch Receiver # 75678. That easier install is actually why I recommend the Draw-Tite over the 2" Curt Trailer Hitch # 13076, as they otherwise have the same capacities, are both rated for use with weight distribution, and have the same clearances. And just...
    view full answer...
  • Is Exhaust Lowered To Install Draw-Tite 75678 Class III Trailer Hitch on 2010 Ford Transit Connect
    According to the installation instructions, lowering the exhaust isn't required during the installation of the Draw-Tite # 75678 on a 2010 Transit Connect. The instructions do call for the spare tire to be lowered to gain access to the frame and then raised back up into position after the install is complete. Installation of the Tekonsha Custom Fit Vehicle Wiring, part # 118585, is not too bad. The unit simply plugs into the factory connectors of the tail lights on each side of the vehicle...
    view full answer...

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Info for this part was:

Employee Lindsey S
Written by:
Lindsey S
Employee Michael H
Expert Research:
Michael H
Employee Jeffrey L
Expert Research:
Jeffrey L
Employee Jeff D
Installed by:
Jeff D
Employee Joshua S
Video Edited:
Joshua S
Employee Jacob T
Video Edited:
Jacob T
Employee Laura H
Updated by:
Laura H
Employee Wilson B
Updated by:
Wilson B
Employee Alexander C
Updated by:
Alexander C
Employee Isabelle B
Updated by:
Isabelle B
Employee Chris R
Video by:
Chris R
Employee Robert C
Test Fit:
Robert C

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