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  1. Custom Fit Vehicle Wiring
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  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

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Custom Fit Vehicle Wiring

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118618 - Custom Fit 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 - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system. 1-800-940-8924 to order Tekonsha custom fit vehicle wiring part number 118618 or order online at etrailer.com. 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 (48)
  • Q & A (0)
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  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring

  • 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 - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system.


Features:

  • 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 - no cutting or splicing of wires
    • Locate connection points in cargo area
    • Plug in 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


Specs:

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


Installation

This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located in your cargo area, behind the tail lights on both the driver's side and passenger's side. You will need to remove the access panel doors to access this harness. Once you've plugged in the T-connector, run the hot lead with the attached fuse holder up to your car battery. Connect the fuse holder to the positive terminal on the battery and insert the provided fuse.


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 flat connector will be stowed in an out-of-the-way location within 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.



118618 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Item # 118618

Installation Details 118618 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 - 118618

Average Customer Rating:  4.8 out of 5 stars   (48 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 - no cutting, splicing or tapping required. Powered ModuLite reduces strain on wiring system.

by:

A year later, no issues. I installed the harness through the inside of the van as opposed to outside along the frame. Much cleaner with maybe 15 minutes more install time. Check [online] for videos.



by:

a whole lot more work than other trailer plug wiring harnesses, having to pull a wire all the way to the battery in the front of the van, but that may be the van manufacturer’s (RAM) fault for not giving enough amperage allowance on the the tailight circuit to begin with. I would suggest getting this modification installed from the factory or the dealer if you have that option.



by:
2020 Ram ProMaster 2500

Great quality, perfect fit, easy instal lation.



by:
Ram ProMaster 2500

The trailer hitch for a Promaster cargo van and the wiring harness I ordered with it are exactly as I expected, nice.
But the shipping, specifically the packaging was a problem. I found a very large box at my door that was split wide open, probably form the hitch smashing through from the inside. There was one small piece of cardboard stapled to the inside that was intended to keep the heavy steel hitch locked in it's corner, it failed. Luckily the UPS people were able to keep the unmarked wire harness box together with the hitch. The fasteners for the hitch were taped into the receiver so they stayed in place. This proves that one size box doesn't fit all. Hope you are listening etrailer?



by:
2018 Ram ProMaster 1500

Pretty easy install. Wires could have been a little longer. I mounted the module high enough to rout the tail light connector to the opposite side (Promaster high roof) then had to lengthen the trailer connector wires about a foot to get the plug located where I wanted it. Even with that though, the hardest part was getting the power wire discreetly routed to my battery. I have installed splice-in kits before, but this plug-and-play version was more convenient, even with the wire length issue.



by:

Works great as it should!



by:

Great service fast delivery



by:

The plug and play wiring harness was an easy install and works great.
Thanks



by:

Quick and easy to connect. Most of the time is spent on accessing the battery.



by:
2014 Dodge ProMaster 3500

I have had no problems with my purchases. I bought a wiring harness and a trailer hitch. Both have worked out well. The hitch is a classA receiver hitch. It fit as expected and the wiring has kept the lights working right.



by:
Dodge Ram Pickup

The Curt trailer hitch receiver was so easy to install on my Ram Promaster 1500 that I was sure I had missed something as it only took about 20 minutes to install. It looks great also.
The customer service and shipping are probably the best I have come across in dealing with any company.



by:

the product kit was thoroughly thought out and complete. The video instruction and personal service at etrailer make this business the best in the world



by:

Install was very easy



by:
2016 Dodge Ram Pickup

Lightning fast delivery! Perfect fit for my 2016 Ram Promaster 1500 Base. I opted to use wire nuts instead of the butt connectors for my installation.I ran the hot wire starting at the battery and worked my way back.and up into the top channel on the drivers side...



by:
2014 Dodge ProMaster 2500

Trailer hitch and wiring kit.
Not yet
installed. The hitch looks solid.
The wiring kit lacked instructions. None.



by:

Amazing product! Great customer service!
installed
on my customers vehicle and sent it down to FL, customer couldn't be happier!!!! the people at etrailer really care about you as a customer and they are really on top of their game. the only place i will ever use for vehicle products!



by:

Yes the product is serving me well , no problems I would buy again,


Comments
It works very well, just what i needed.
David Y - 12/22/2018


by:

easy to order and quick delivery



by:
Ram ProMaster 2500

Ordered it and it arrived on time. Directions were easy with minor wiring knowledge required (crimping, wiring layout, securing).

Literally plug and play for the Promaster I drive. Worked first time!



by:
2017 Ram ProMaster 2500

The hitch I ordered from etrailer arrived exactly when they said was properly packaged and fit very nicely on my 2017 Promaster. Thanks



by:
2020 Ram ProMaster 2500

great product great price



by:
2019 Ram ProMaster 2500

Shipping was fast but could have been better protected. All parts and pieces were there, but it looked like it took a beating through the single layer of plastic wrap used in shipping.



by:

Perfect fit and easy installation. Easy follow instructions



by:
2014 Dodge ProMaster 1500

The hitch I buying is really excellent short and easy to install with a good explanation for the installation I'm satisfied a100% with the purchase



by:
2014 Dodge ProMaster 1500

The hitch I buying is really excellent short and easy to install with a good explanation for the installation I'm satisfied a100% with the purchase


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Show More Reviews

Ask the Experts about this Tekonsha Custom Fit Vehicle Wiring



  • Trailer Wiring Harness on 2019 Dodge Promaster 2500-No Output on Brake Lamp/Turn Signal Circuits
    If you have power on the green and yellow wire leading from the T connection in the vehicle's taillight wiring harness to the converter box, but no power on those wires exiting the converter box itself, then the converter is bad and should be replaced. You'll want to check a couple of things first, though. Is the fuse installed in the yellow fuse holder at the battery connection? Is the fuse fully seated? If not, it would prevent the converter box from outputting anything. Are there...
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  • Recommended Trailer Hitch and Wiring for 2015 Dodge ProMaster 2500
    The Draw-Tite Class III Max Frame Round Tube Receiver Hitch # 75882 referenced in your question is confirmed to fit the 2015 Dodge ProMaster 2500, as long as it is not the EXT model. This Draw-Tite Hitch does provide the highest tongue weight capacity of 750 pounds and towing capacity of 6,000 pounds available for trailer hitches confirmed to fit this vehicle. I have attached an installation video on a 2014 ProMaster 2500 for you to check out. This trailer hitch does not include a wiring...
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  • Is Exhaust Tip Extension Needed After Installing a Trailer Hitch on a 2015 Ram ProMaster 1500
    Looking at your picture you will not need an exhaust tip extension. Actually, if you used one it would fit around the existing tip making the pipe closer to the hitch. The fact that the exhaust exits down and not at the hitch and the pipe does not make contact with the hitch is perfectly fine. It looks a lot like hitch # C13295 that we have installed on a similar vehicle as your 2015 Ram ProMaster 1500. I have linked a video showing the installation. The exhaust was in the exact same location...
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  • Troubleshooting Trailer Brake Lights Not Working With 2021 Ram ProMaster 2500
    To begin troubleshooting this problem I recommend checking the connections on your T-One Vehicle Wiring Harness # 118618. Often when one function is not working it is due to a set of connectors not seated together properly. Try disconnecting and reconnecting the harness to ensure the connectors are seated together properly. While you are checking the connection it might be a good idea to give the wires a quick inspection. Although it is a new wiring harness, it is possible a wire got...
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  • Recommended Hidden Trailer Hitch for 2018 Ram ProMaster 2500
    The trailer hitch I highly recommend for your 2018 Ram ProMaster 2500 is the Curt # C13295 because it has a concealed crosstube and is a bolt-on installation that will not require drilling into your ProMaster's frame to install. This Class III, 2" trailer hitch is almost entirely hidden behind your bumper. This hitch has a black powder coat finish which helps protect it from corrosion and also has a 5,000 lb towing capacity and 500 lb tongue weight capacity. The Curt # C13295 is made in...
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  • Trailer Hitch and Wiring Recommendations for a 2017 Ram ProMaster 1500 Extended Body
    For the 2017 Ram ProMaster 1500 we are using EXT to refer to the extended body models which sounds like what you have. Draw-Tite trailer hitch # 76050 does indeed fit the extended body models. A lift is not required for installation but jacking up the rear of the vehicle will make it easier to install. I also recommend etrailer.com 2-3/4" Rise or 4" Drop Ball Mount Kit - 7,500 lbs Item # EBMK4. It comes with a ball mount with a 2-3/4 inch rise or 4 inch drop, interchangeable ball set,...
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  • Recommended Trailer Hitch For A 2022 Ram Pro Master 2500
    When installing a trailer hitch on your 2022 Ram Pro Master 2500 The Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2 inch # 76050 is confirmed to fit your vehicle. The Draw-Tite hitch has an easy, bolt-on installation with no welding required. It has a black powder coat finish that covers an e-coat base for superior rust protection. The trailer hitch has a maximum gross trailer weight of 5,000 pounds and has a maximum tongue weight of 500 pounds. I would recommend...
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  • Troubleshooting Brake Controller Install that Does Not Show Voltage on Circuit Tester
    Brake controllers don't always work with 7-way circuit testers like you mentioned. The brake controller needs to see the amperage draw of brake magnets to know that a trailer is connected and a 7-way circuit tester won't provide that. This prevents the controller from registering like what you mentioned. Since the controller worked when you hooked it up to a trailer that means it should be fine. Now the trailer lights are most likely related to the 4-way trailer wiring of the harness vehicle...
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  • Parts Needed for Trailer Brake Controller Installation in 2015 Ram ProMaster 2500
    Trailer brake controller installation in your 2015 Ram ProMaster 2500 will be hardwired since there is no under-dash connection port. You can install any brand and model of brake controller using our install kit # ETBC7. This kit is all inclusive apart from the controller itself. The van will need to have a 4-pole wiring harness in place too; if it does not have one you can use kit # 118618. Among the highest-rated controllers we sell are the Prodigy series, models P2 # 90885 and the P3...
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  • Will Curt Trailer Hitch # C13207 Fit a 2017 Ram ProMaster 2500 with Rear Step
    The restrictions for the hitches that fit the 2017 Ram ProMaster 2500 only pertain to if it is an EXT model or not. Curt trailer hitch # C13207 does not fit the EXT models. If the step you have installed is the step bumper then there should not be a problem. If it is a side step then you will want to look over the linked instructions for the hitch to see where on the vehicle it installs and if that conflicts with where the step installs. If you do have an EXT model then the comparable...
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  • What Hitch Does Not Require Grounding Bolt Modification on My 2021 Ram ProMaster 2500?
    For avoiding modifications to the grounding bolt on your 2021 Ram ProMaster 2500, I recommend the Curt Trailer Hitch Receiver - Custom Fit - Class III - 2" # C13295. Since this Curt hitch installs behind the bumper beam, it will not install anywhere near the grounding bolt. Another great feature about the hitch is that it comes with a super high-quality gloss outer coating over the base coat to provide you with superior protection against rust and corrosion. If you need a wiring harness...
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  • Hitch Recommendation for Promaster 3500 Extended
    For your 2015 Ram ProMaster 3500 the Draw Tite # 76050 is a confirmed fit and would work great. It has more than enough capacity and the shortest install time listed of the hitches that fit your vehicle. You will need to start with a 4-way (if you do not have one). For that you would want the # 118618. Now if your trailer does not have brakes all you would need is the part # 37185 as an adapter to convert the 4-way to a 7-way. If you do have trailer brakes you would need the # ETBC7...
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  • Recommended Trailer Hitch For 2015 Ram ProMaster 2500
    The trailer hitch I recommend for your 2015 Ram ProMaster 2500 is the Curt trailer hitch, part # C13295. This is a Class lll trailer hitch and it has a 2-inch receiver opening. I have attached a link to an installation video you can check out. If you plan on doing some towing you might be interested in etrailer ball mount kit # 989900. It comes with 2 ball mounts; one with a 3/4 inch rise or 2 inch drop and one with a 2-3/4 inch rise or 4 inch drop. It also includes a 1-7/8 inch ball,...
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  • Recommended Brake Controller Wiring Harness for 2019 Ram ProMaster 3500
    For the 2019 Ram ProMaster 3500 there is not a direct wiring harness. If you want to use the P3 # 90195 then you will need to use the kit # ETBC7 to hardwire it. If you don't have the factory tow package, you will also need the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118618. If you want the complete wiring harness that also will include that brake controller wiring I recommend the Tekonsha OEM Replacement Vehicle Wiring Harness w Brake Controller Adapter -...
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  • Trailer Hitch Receiver For 2020 Ram ProMaster 2500 That Works Around In-Use Grounding Bolt
    I have another option for you, but the grounding nut you show in your picture will interfere with the installation of the Curt Trailer Hitch Receiver - Custom Fit - Class III - 2" # C13207 you were looking at, and would need to be relocated. Instead I recommend the Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2" # 75882 which is also confirmed to fit your 2020 Ram ProMaster 2500, but the hitch only goes on the bottom of the frame rails and not the sides so it will...
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  • Hitch For 2021 Winnebago Travato on Promaster 3500 ext
    For your 2021 RAM ProMaster 3500 EXT with the Winnebago Travato body, the Curt C13704 is not a confirmed fit for the EXT models. I recommend the Draw-Tite # 76050 Class-3 hitch which is rated for 500 pounds tongue weight and 5000 pounds towing. Features 2" receiver and strong square tube design. If you don't already have these parts, the etrailer # 989891 trailer ball and mount kit is a good place to start. If you will need your hitch for towing and don't already have a 4-way or 7-way...
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  • Recommended Trailer Hitch That Won't Interfere With Grounding Bolt on 2021 Ram ProMaster 2500
    In order to not interfere with the grounding bolt on your 2021 Ram ProMaster 2500 I recommend the Draw-Tite Max-Frame Trailer Hitch Receiver # 75882. The hitch will bolt on to the bottom of the frame where the grounding bolt is located, so it will not be in the way or require any modification to your grounding bolt. If you plan on using the hitch for towing you will also need wiring. I recommend the Tekonsha T-One Vehicle Wiring Harness # 118618 to add a 4-way connection. If you need a...
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  • Best Trailer Hitch For A 2021 Ram ProMaster 2500 That Can Install Around The In-Use Grounding Bolt
    If the grounding nut/bolt are being used on your 2021 Ram ProMaster 2500, you are correct in that the Curt # C13207 will not be the best option for you. With that said, I recommend going with the Curt # C13295. This will install behind the bumper beam (pictured) and will not get anywhere near that ground. This is also American made and will give you 5,000 pounds of towing capacity and 500 pounds of tongue weight. If you were planning on using the hitch for towing, I also recommend getting...
    view full answer...
    Image 1 for
  • Wiring Harness and Receiver Hitch for the 2022 Ram ProMaster 3500
    For wiring harness for the 2022 Ram ProMaster 3500EXT, I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, # 118618. The T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. At this point no hitch manufacturer has released a verified fit for the 2022 Ram ProMaster.
    view full answer...
  • Availability of a Custom Wiring Adapter for a Brake Controller on a 2017 Ram ProMaster 2500
    For the 2017 Ram ProMaster 2500 van, the wiring to connect a brake controller will have to be both installed and spliced into existing OEM wiring. There are no custom plug in wiring harness available for this model vehicle. To install a brake controller, like the Tekonsha Prodigy P2 # 90885, a 4-way wiring harness and a 7-way trailer connector will need to be installed. For the 4-way harness I recommend the Tekonsha T-One Vehicle Wiring Harness, # 118618. This harness is designed to plug...
    view full answer...
  • Hitch, Wiring and Brake Controller for 2018 Ram ProMaster 3500
    Curt 2-inch hitch # C13207 will give you both the highest available hitch tow rating of 7500-lbs and a simple no-drill installation on your ProMaster 3500. This hitch should take only about half as long to install as the Draw-Tite # 75882, about a half hour or so, plus it is USA-made. An installation video showing a ProMaster 2500 is linked for you along with a picture of a completed install. If you need a 4-pole wiring harness I recommend Tekonsha's custom kit # 118618 which is mostly...
    view full answer...
    Image 1 for
  • Comparing Trailer Hitch Options for a 2019 Ram ProMaster 2500
    The trailer hitch options for a 2019 Ram ProMaster 2500 can be broken down into two categories, hidden and visible. The hidden options do not have a crosstube under the bumper and the visible option does. The hidden crosstube is harder to install. If you prefer aesthetics over install difficulty then go with the hidden but if you prefer an easy install over aesthetics then go with the visible crosstube. I prefer Curt hitches so part # C13207 for visible or part # C13295 for hidden. The...
    view full answer...
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  • Towing Capacity of 2020 Ram ProMaster 1500
    The max towing capacity of a 2020 Ram ProMaster 1500 is 6,910 lbs for low roof models with 118" wheelbase, 6,800 lbs for low roof models with 136" wheelbase, and 6,700 lbs for high roof models with 136" wheelbase. These figures apply to both factory and aftermarket hitches. If you don't already have a trailer hitch I recommend the Curt Trailer Hitch Receiver part # C13207 which offers an easy bolt-on install. You'll then need trailer wiring for which I recommend the T-One Vehicle Wiring...
    view full answer...
  • Parts Needed to Install 7-Way and Brake Controller in 2020 Ram ProMaster 2500 wo Tow Package
    To install a brake controller like the Redarc Tow Pro Liberty part # RED24FR in your 2020 Ram Promaster would first require you to install a 4-way like the part # 118618 that fits your vehicle and then convert it to a 7-way with the part # ETBC7 which comes with everything needed to wire in a brake controller and convert to a 7-way. The Curt Class III part # C13295 would be a great option for a hitch as well.
    view full answer...


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Info for this part was:

Employee Mike L
Expert Research:
Mike L
Employee Michael H
Expert Research:
Michael H
Employee Jameson C
Expert Research:
Jameson C
Employee Jeff D
Installed by:
Jeff D
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:
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Employee Dustin K
Video by:
Dustin K
Employee Bradley B
Test Fit:
Bradley B

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