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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 # 118604
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Custom Fit Vehicle Wiring

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Tekonsha Trailer Hitch Wiring - 118604
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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. 1-800-496-5010 to order Tekonsha custom fit vehicle wiring part number 118604 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.
  • All Info
  • Reviews (3)
  • Q & A (0)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118604

  • 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 in trunk
    • 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 inside your trunk, behind the tail lights on both the driver's side and passenger's side. You will need to remove the threshold panel and some of the trunk liner to access the 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.

Once installation is complete, the 4-way flat connector will be stowed within your trunk.

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.

118604 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite

Installation Details 118604 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 - 118604

Average Customer Rating:  5.0 out of 5 stars   (3 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.

2013 Chevrolet Malibu

I originally purchased the T-One 118576 wiring harness for my 2013 Malibu LT that was manufactured in the US, which is the kit that the manufacturer recommends for that car. With this kit, all 3 trailer lights illuminated when the taillights were on without pressing the brakes. Etrailer sent me anther kit which did the same thing. etrailer then contacted the manufacturer and learned that some Malibus manufactured in the States have Canadian wiring which requires another kit. etrailer immediately sent me the T-One 118604 wiring harness for Malibus that are made in Canada. That one worked. With each replacement kit they sent, they also emailed me a prepaid return shipping label. I am very happy with etrailer's service. The installation is very easy. The only challenging part is routing the power wire from the trunk to the battery in the engine compartment. The rest is just unplugging and plugging in connectors. Hopefully the manufacturer will provided some additional information for future buyers to determine if there Malibu is US or Canadian wired.

The products are working just fine. I am very happy with them.Thanks for checking
Jerry - 01/30/2018

2013 Chevrolet Malibu

Plug and play. With basic wiring knowledge hook up easy.


All installed


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

  • Trailer Wiring Recommendation for US and Canada Model 2013 Chevy Malibu
    If you bought your 2013 Chevy Malibu in the US then you have a US model and would want the Tow Ready Custom Fit Vehicle Wiring # 118576. If you bought your vehicle in Canada then you would want the # 118604. If you are still confused the easiest way would be for you to contact your Chevy dealer and give them your VIN number and they should be able to tell you. From the research I did it looks like if your VIN starts with the numbers 1,4 or 5 it was made in the US and if it starts with...
    view full answer...
  • Trailer Wiring Harness for a 2015 Chevy Malibu
    It is not recommended to use the smaller trunk battery to install a trailer wiring harness on a 2015 Chevy Malibu. That small battery is not rated as high as the regular battery under the hood and using it could result in the trailer wiring harness not working properly. There are different trailer wiring harnesses recommended for different models of the 2015 Malibu. For a US or Canadian model that is NOT an LTZ use # 118604. For a US model that IS an LTZ use # 118602.
    view full answer...
  • Trailer Hitch and Wiring for a 2015 Chevy Malibu LT
    Discontinued trailer hitch 90237 fits the 2014 Chevy Impala LS, LT, and LTZ models but your 2015 Chevy Malibu will require a different hitch. For your Malibu LT you can use Draw-Tite trailer hitch # 36538. For the correct ball mount use # 36061. To add a 1-7/8 inch ball use # 19256 and for a 2 inch ball use # 19258. And for a trailer wiring harness use # 118604 (fits US models excluding the LTZ).
    view full answer...
  • Towing Capacity of a 2014 Chevy Malibu LS 2.5L Ecotec and Trailer Hitch and Wiring Recommendations
    I checked the owner's manual for the 2014 Chevy Malibu and it states that the towing capacity of the vehicle, no matter which motor or trim level it has, is 1,000 pounds gross trailer weight. Trailer hitches such as # C12115 have their own ratings but you always go by the lowest rating, vehicle or hitch, and in this case the vehicle is lower. That means even though the hitch is rated higher you are limited to 1,000 pounds gross trailer weight. If the trailer weighs 925 pounds when loaded...
    view full answer...
  • Will Curt Trailer Hitch C121153 Fit a 2016 Chevy Malibu Limited LT
    Curt trailer hitch # C12115 will fit all US models of the 2016 Chevy Malibu Limited including your LT. The recommended ball mount is # C45017. For a 1-7/8 inch ball use # 19256 and for a 2 inch ball use # 19258 and for a pin and clip use # F-4. For a trailer wiring harness I recommend # 118604 to add a 4-Way flat connector to the rear of the vehicle.
    view full answer...
  • Trailer Hitch Fit for 2015 Chevy Malibu
    The Draw-Tite # 75278 isn't a fit for a Malibu, it's a fit for various GM minivans, such as: • 1999 - 2005 Pontiac Montana • 2005 - 2007 Saturn Relay • 1997 - 2004 Oldsmobile Silhouette • 2005 - 2007 Buick Terraza • 1997 - 1999 Pontiac Trans Sport Van • 2005 - 2009 Chevrolet Uplander • 1997 - 2005 Chevrolet Venture • 2005 - 2009 Pontiac Montana SV6 Extended Wheelbase • 2005 - 2009 Pontiac Montana SV6 Regular Wheelbase For your 2015 Chevy Malibu, I'd recommend the Curt Class II hitch,...
    view full answer...
  • Trailer Hitch for Carrying Mobility Scooter with 2014 Chevy Malibu
    Because the 2014 Chevy Malibu uses a Class II hitch like the Curt # C12115 that has a 1-1/4 inch receiver opening, it wouldn't be a good vehicle to carry a mobility scooter with, unless you can find one that's compatible with a 1-1/4 inch hitch. Unfortunately, all the scooter carriers we offer are only compatible with a 2 inch receiver. The best solution I could offer would be a small trailer like # K2MMT4X6. To equip your Malibu for towing, in addition to the hitch you'll also need a...
    view full answer...

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Info for this part was:

Employee Lindsey S
Written by:
Lindsey S
Employee Joshua S
Video by:
Joshua S
Employee Kathleen M
Video Edited:
Kathleen M
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 Jared G
Test Fit:
Jared G

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