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  1. Custom Fit Vehicle Wiring
  2. Tekonsha
  3. Custom Fit
  4. Trailer Hitch Wiring
  5. 4 Flat
  6. No Converter
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector

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

Item # 118315
Our Price: $22.84
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Custom Fit Vehicle Wiring

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Custom Fit Vehicle Wiring 118315 - 4 Flat - Tekonsha
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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. 1-636-306-4830 to order Tekonsha custom fit vehicle wiring part number 118315 or order online at Free expert support on all Tekonsha products. Great prices 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 (120)
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Tekonsha Custom Fit Vehicle Wiring - 118315

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No 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.


  • 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 along frame rail
    • Plug in T-connector
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage: 7.5 amps per circuit
  • 1-Year limited warranty


T-One Connection Location Points

This custom-fit T-One connector plugs into your vehicle's wiring harness, which is located beneath your vehicle, along the driver's-side frame rail.

Once installation is complete, the 4-way flat 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 plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.

118315 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118315 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118315

Average Customer Rating:  4.9 out of 5 stars   (120 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.


Excellent product, easy to install, works perfectly. Needed to drill a 1/8 inch hole as opposed to the 3/32 in the instructions for the ground wire connection but a simple fix. Installed it to later connect an LED tailgate light bar.

Still works great, high quality product.
Paul K - 12/27/2021

1991 GMC C/K Series Pickup

Exactly what I needed, plug n play!

1992 Chevrolet C/K Series Pickup

I had been putting this off thinking that I was going to have to splice into the wiring system on my 1992 Chevy WT. This could not have been easier. Highly recommended.


It is an excellent harness and connector. i have had no problems what so ever. I t has worked great form me.


Perfect for my truck
Contacted etrailer
and they took time no rush to find the perfect part free shipping no issues
I will call etrailer first to assist me with my next project

1992 Chevrolet C/K Series Pickup

This made my brake instillation kit extremly easy. Must have for a new 7 plole pig tail. No cutting wires it was all plug and play.

1997 Chevrolet Silverado

trailer wiring was high quality and worked well on my 1997 Silverado.

1997 Chevrolet C/K Series Pickup

This was a very simple plugin installation. I did have to drill a hole for a self tapping screw for the ground wire (the drill size was a little larger than what the instructions called for). Just make sure you put it where the spare tire will not come into contact with it. (I had to do it twice). I'm very happy with my new hitch and wire harness. Shipping was fast. I think I ordered it Friday morning and received it Monday or Tuesday.

So far so good. No problems at all.
John W - 12/26/2016

1992 Chevrolet C/K Series Pickup

Every thing was as asdvertised. I only wish that the wiring harness was one connection greater in that I have to wire my back up lights to release the brakes on the trailer when backing up

Ken where do you plug this in on a silverado? Where on the wiring harness? Thanks.
-- comment by: Keilan - 05/16/2013

1996 Chevrolet C/K Series Pickup

Great shopping experience, fast delivery and no splicing my wiring harness I used this to make my 60" led lights on the truck bumper work... HAPPY HAPPY HAPPY

Still working great with no problems still satisfied
Tony H - 11/10/2016


The harness made it very easy to install in my truck.

1994 Chevrolet C/K Series Pickup

The trailer light hook-up for my '94 Chevy truck came very quickly, even though I picked economy shipping. I was delighted that it came so fast, but it was a few days before I got the time to install it.
I was expecting to take apart my lights and hook in behind the light bulbs like I did on my Ford E250 which was simple enough. (The harness on the E250 is still going strong several years later by the way.)
This light kit only took about 15 minutes to install. The instructions were simple and easy to follow. What took the most time was rounding up a couple of zip ties and drilling a little hole to put a ground screw in. This was so quick and very, very easy.

I do lawn mowing and landscaping. I use my trailer a lot. The good people at the package store where I bought my trailer were suggesting a person to custom install a light harness on my vehicle for a little more than a hundred dollars. This etrailer kit cost me less than $$.00 all told, part and shipping included.
These people at etrailer are so very helpful and can save you so much money and frustration. You owe it to yourself to give them a try.

Thanks etrailer. Awesome product and service. I will definitely use you again. In fact, I expect to order a frame mount hitch receiver from you later this spring.

1993 Chevrolet C/K Series Pickup

I received the wire T-harness for the rear lights on my 1993 Chevrolet truck Wednesday and I installed it Thursday, March 23. It was easy to install and it works fine. Thank you for your prompt service.

Michael S., Columbia, TN.

Yes, I installed the wiring t-harness on my 1993 Chevrolet Silverado on 3-23-2017 and it is working fine. I hooked-up my trailer last Thursday and the lights are working fine. I should have purchased it a long time ago.
Michael S - 03/26/2018

1998 Chevrolet C/K Series Pickup

Installation on my Chevy C1500 was a breeze. Simple plug and play, secured w/ zip tie then attached ground to body, adding a dab of electrical grease (wire to body). I purchased the flat 4 mounting bracket, drilled two holes , and mounted it on the bottom of bumper near the ball. A dab of electrical grease on the flat 4 dust cap and it's good to go. I must of looked at it four times afterwards, thinking, man that looks good. Just buy it, you've already been thinking about it.

1998 Chevrolet C/K Series Pickup

Heavier built than basic plug and play 4 way harness. 10 min to install.

I haul trailers at least once a week .This product has been great. It has worked every time, no problems
Kevin - 07/05/2020

1997 Chevrolet C/K Series Pickup

Exactly what I ordered. A no brainer. Literally a plug and go deal here. Absolutly no splicing or destroying your factory wire harness. The other trailer light connector styles require you to cut and splice in a wire allowing for moisture to cause corrosion. A little electirical grease before connecting it and my connections have been corrosion free for over a year now. Very satisfied. Have recomended time and time again. I pull trailers every day and this product has held up. Plan on purchasing 4 more in the future for my other trucks.

1998 Chevrolet C/K Series Pickup

Ordered the Curt trailer hitch and trailer wiring harness for my 1998 Chevy . Was shipped out the day I ordered. Extremely pleased with products! Was searching for a no drill install and this was perfect. Bolted right up and harness was a simple unplug and plug back in. Total install time was 45 minutes and that was by myself laying on garage floor. Price was on point as well. I highly recommend .

1994 GMC C/K Series Pickup

everything was perfect. Great price, accurate fit for my truck. The Tekonsha trailering wire harness kit went on easily and works perfect. Now when i trailer i have lights for safety. Thanks guys

1993 Chevrolet C/K Series Pickup

Stupid me!!! I have been wiring trailers on my own for years...
Finding the trailer wiring set that simply plugs in on saved me time, frustration and laying in the dirt! On top of that, it was delivered quick and works great...

Thanks etrailer
Larry Bowers / Utah

1998 GMC C/K Series Pickup

Exact fit for my 1998 GMC truck. Installation was easy and straight forward as advertised. Will be returning to etrailer for all my future truck and trailer needs.

The item that I purchased a year ago is as great today as the day I installed it. This is a great product.
Dick D - 10/01/2016

1997 GMC C/K Series Pickup

The led trailer lights and wiring harness all worked well! Cured my trailer light
Problem totally!!


I bought a wiring harness for my 97 gmc truck. It was easy to install and has been working great for me for a year now. Would highly recommend it for anyone looking for a easy great working product.

1988 Chevrolet Silverado

Great company to buy from fast service and shipping.. product was exactly as advertised. I bought a wireing harness for my 1988 chevy silverado to hook my pop up to and the harness fit perfect. I will defenitley be shopping at again.

2010 Chevrolet Silverado

A perfect fit on my 1989 chevy 1500 Silverado .
Just snap together and you're done. No cutting or splicing wires. Took all of 10 minutes. Great product.

It works great
keith a - 05/01/2016


I was a little concerned when I opened the package and the product I received did not look exactly like what was pictured in the catalog, but it fit perfectly. I've had an on-again-off-again problem with my "professionally" wired trailer lights from day one. The eTrailer wiring T eliminated a rat's nest of wires, fixed my problem, I did it myself, and I saved big bucks!

Show More Reviews

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

  • Fit of Tow Ready T-One Connector # 118315 on 1989 Chevy K1500 w/ Custom Bumper
    The Tow Ready # 118315 is designed to fit a 1989 Chevy K1500 with a stock bumper. The lamps on your bumper should plug into the factory wiring harness on the driver's side frame rail. The # 118315 will plug inline at that connection as long as it hasn't been altered. If your connector looks like what's shown in the photo and video I've linked for you, the # 118315 should fit without cutting or splicing.
    view full answer...
  • Connection Point for T-One Vehicle Wiring Harness 4-Way Trailer Connector # 118315, 1998 GMC Pickup
    The T-One Vehicle Wiring Harness with 4 Pole Trailer Connector, # 118315, is a fit for your 1998 GMC pickup. The connection point could be difficult to find unless you know where to look. What you are looking for is a connector that leads to your taillight wiring. It should be located along the driver side frame rail near the bumper. I have included a link to the installation instructions below.
    view full answer...
  • Trailer Lights Flash with Vehicle Flashers and Go Out when Stepping on the Brakes
    So it sounds like the flashers are tied into the running light circuit on the truck side. I am not sure it this is how it is supposed to be or if there is a wiring issue on the truck. The correct 4-Way for a 1998 GMC C/K series is # 118315. It just plugs in line with the vehicle tail light harness, see instructions link. Applying the brakes may be causing the trailer lights to go out while the flashers are on because it is too much draw on the wiring which is causing the lights not to...
    view full answer...
  • Trailer Wiring Harness for a 1994 GMC C/K Series Pickup Truck
    In 1994 the Sierra was just a trim level of the C/K series GM trucks. It wasn't until 1999 that the Sierra started to take the place of the C or K designation and that transition was complete in 2000. For a trailer wiring harness that will fit your truck I recommend the Tow Ready harness # 118315. It plugs in line with the vehicle tail light wiring. I have linked a video showing an example installation for you. A mounting bracket such as # 18144 is also recommended.
    view full answer...
  • Will 4 Pole to 5 Pole Trailer Wiring Adapter Fit a 1995 GMC C/K Series Pickup Truck
    Yes, all you will need is to plug the 4-Way end into an existing 4-Way on your 1995 GMC pickup and then use the included quick splice connector in adapter # 20036 to connect the blue wire to a reverse light wire on the truck. Then it will activate the electric reverse lockout on the surge coupler when the truck is put in reverse. If you need to add a 4-Way to the truck you can use # 118315.
    view full answer...
  • How Can You Tell if a 1997 Chevrolet Silverado Has Factory Trailer Wiring
    The 1997 Chevrolet Silverado has some of the wiring in place to connect a brake controller, but it does not have the provision for plugging the controller in under the dash. There is an orange and blue wire that is run from the rear drivers side frame rail to the engine compartment. The blue wire carries the brake controller output, and the orange wire if for the 12 volt trailer lead. The ends of these wires would connect to the trailer connector at the rear of the truck. In the engine...
    view full answer...
  • Will Curt Trailer Hitch be Hidden Behind License Plate on 1997 Chevy C/K Pickup with Roll Pan Bumper
    Yes, the Curt Trailer Hitch, # 13942, will be hidden behind the spring loaded license plate on your 1997 Chevrolet C/K Series Pickup with a roll pan bumper. I have included a link to the installation instructions for this hitch for reference. This is the only hitch specifically designed for use if the truck has a roll pan. For wiring, you will need Tow Ready Custom Fit Vehicle Wiring, # 118315. I have included a link to the installation details and video for reference.
    view full answer...
  • Trailer Hitch Recommendation for a 1996 Chevy C/K Series 1500 Pickup Truck with Dual Exhaust
    The Curt Trailer Hitch, # 13942, is designed to fit if the truck has a roll pan. There is no restriction if the truck has dual exhaust. I have included a link to the installation instructions for this hitch for reference. This is the only hitch specifically designed for use if the truck has a roll pan. I have included a link to all of the trailer hitch options for a 1996 Chevy C/K 1500. Just select your specific truck style from the pull down menu under where it reads Select Vehicle Style...
    view full answer...
  • Recommended Trailer Wiring Harness For 1992 Chevrolet 1500 Pickup Truck
    To add an additional 4-way connector on the 1992 Chevrolet 1500, I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector, part # 118315. This plugs into the connection points along the frame rail under the truck on the driver side. There is no cutting or splicing into the truck wiring to install this. When working with electrical connectors I recommend using dielectric grease like part # 11755. This keeps dirt and moisture out of the electrical connections and...
    view full answer...
  • Wiring to Add 5-Way Harness on 1992 Chevy Silverado to Connect to Boat Trailer
    To add a wiring harness to your 1992 Chevy Silverado for your boat trailer you need to first add a 4-flat, the T-One Vehicle Wiring Harness # 118315; I've attached a link showing this harness being installed on a similar truck for you to check out. From there you need an adapter, the Tow Ready 4 Pole to 5 Pole Trailer Wiring Adapter # 20036 to give you a 5-flat on your Silverado.
    view full answer...
  • 4 Pole Trailer Wiring Harness for 1991 Chevy C/K Pickup Truck
    The Tekonsha # 119130 is indeed designed to tap directly into a vehicle's taillight circuits. Your truck uses a combined wiring system, so the converter box would be providing circuit protection to isolate the truck wiring from any short circuits that might occur in the trailer wiring. To install, the green wire taps into the right turn circuit, the yellow wire into the left, the brown into the taillights and the red and the while would be grounded to the truck. There is a plug and play...
    view full answer...
  • 7-Way and 4-Way Recommendation for 1993 Chev C1500
    For your 1993 Chevy C1500 you'd want to start with the 4-Way kit part # 118315 which is a confirmed fit and then to convert it to a 7-way/4-way combo you'd just need the # 37185 and you'd be set.
    view full answer...
  • Recommended Trailer Hitch Receiver For 1995 GMC Sierra K1500
    As long as the tire on the 20" spare is the height as the factory tires on your 1995 GMC Sierra K1500, and your truck has the standard or step bumper you will be able to use the Draw-Tite Trailer Hitch Receiver - Multi Fit - Class IV - 2" # 37130. This hitch has a 700lb tongue weight rating and a 7000lb trailer weight rating when NOT using a weight distribution system, or 1200lb tongue weight and 12000lb trailer weight if you are using a weight distribution system. Keep in mind that these...
    view full answer...
  • Determining the Function of a Wire Labeled YEL FEED BRK SW on a 1994 Chevy C/K2500
    The wire you are referring to is probably the center high mount stop light wire or CHMSL. This wire would be used for a third brake light function for example on a camper shell. You can test it by using a circuit tester like # PTW2993. If the wire shows a signal only when the brakes are pressed, and not when the turn signals are on or flashers are engaged, then it is the CHMSL. If it does show a signal with the blinkers and flashers then it is a taillight brake light wire that also carries...
    view full answer...
  • Trailer Wiring Does Not Work on a 1999 Chevy Silverado or C/K Series Pickup
    Does the converter you are using by any chance require a direct connection to the vehicle battery to actually power the trailer lights? Some converters are powered and they get the signals from the tail light wiring but the power comes from the vehicle battery. It could also be a bad converter box. Use your test light to test the wires going into the converter box to make sure they are correct. If they are not correct that indicates a problem with the truck wiring. If they are correct...
    view full answer...
  • Power Wire for a 7 Way on a 1996 Chevy Pick Up
    If your 1996 Chevy pickup did not come with a factory 7 way, you will need to run a power wire from the battery back to a 7 way that you will install. However, if your trailer does not need an auxiliary power supply, you can omit running the power wire up to the battery. I assume you will be needing to add a 7 Way plug. If you already have a 4 Way trailer connector, you will simply need part # ETBC7 to complete the installation of a 7 Way. If you do not already have a 4 Way connector...
    view full answer...
  • Will Draw-Tite Trailer Hitch Fit 1996 Chevrolet C/K Pickup With Step-Side Bed
    The Draw-Tite Max-Frame Trailer Hitch Receiver, part # 75099 is designed to work with all models of the 1996 C/K pickups with a standard or step-bumper, so it will work fine with your step-side. This is a Class lll hitch and it has a 2-inch receiver opening. 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...
    view full answer...
  • Adding a 4-Way Flat Trailer Connector to a 1992 Chevrolet C/K Series Cab and Chassis
    A 9-pole to 4-Way flat adapter is not available since it is a combination that is quite rare. You would either have to make one or install a separate 4-Way. The easiest solution would be to install the Tow Ready Custom Fit Vehicle Wiring, # 118315. I have included a link to the installation instructions for you. The 4-Way plugs in line with the tail light wiring on your 1992 Cab and Chassis model Chevy C/K.
    view full answer...
  • Troubleshooting Trailer Wiring Issues When Vehicle Headlights Are On
    It sounds like there is too much of a draw when your headlights are on and that makes everything else work improperly. There are two possibilities, but it sounds like a bad ground wire versus a bad wiring harness. I recommend checking your ground to make sure it is free of corrosion and rust and has a bare metal to metal connection. One easy way to test this is to take a length of wire and just connect it to your negative battery terminal and then the location of your ground wire on...
    view full answer...
  • Brake Controller and Install Recommendation for a 1999 GMC 1500 Truck
    You will need to start with a 4-way (if you do not have one). For that you would want the # 118315. From there you would need to convert the 4-way to a 7-way so that you can install the brake controller. For that you will want the Brake Controller Install Kit and 7-Way Adapter part # ETBC7. I attached installation instructions and an install video for this product as well. For a brake controller I would recommend the Prodigy P3 Brake Controller part # 90195. This is our best selling brake...
    view full answer...
  • Adding a 4- and 7-Way Trailer Connector to a 1997 GMC 2500 Series Pickup Truck
    If your 1997 GMC Sierra 2500 has a plug with a round cap up above the spare tire or in that general area then it is likely that 4- and 7-Way connector # 74682 will fit. Otherwise in order to install a 4- and 7-Way you will need # ETBC7. The truck would need to have a 4-Way flat connector to plug into the ETBC7. If it doesn't then the first step is to install a 4-Way on the truck, # 118315, and then install the ETBC7. I have included some links that show and explain the ETBC7 installation...
    view full answer...
  • Will Draw-Tite Trailer Hitch 41901 Fit a 1994 Chevy C/K Series 3500 Crew Cab Dually Long Bed
    The frame on your 1994 Chevy C/K series truck indicates that it is NOT a cab and chassis model (which normally have narrower frames) so you can use hitch # 41901. I have included a link to the installation instructions for you. I also recommend etrailer ball mount # EBMK2416. It includes a ball mount, 2 balls, a hitch pin with clip, and a storage bag. If you need to add trailer wiring use # 118315.
    view full answer...
  • Trailer Hitch Recommendation for a 1988 GMC SLE Truck Sportside
    For your 1988 GMC SLE with a sportside bed you would want the Draw Tite Hitch part # 75033. As long as you have a standard or step bumper this would be the correct hitch for you. The part # 75034 that you referenced fits older model GMC trucks so it would not work for you. To complete your towing setup you may also be interested in the following products: ball mount kit part # 989900 Trailer wiring harness part # 118315
    view full answer...
  • Installing Trailer Brake Controller and 7-way Trailer Wiring Harness on 1997 Chevy Silverado
    To prepare your Silverado for towing, you will need a brake controller, the install kit # ETBC7, and the T-1 connector, part # 118315 to tap into the truck lighting circuits. Although we offer many different brake controllers, I would recommend a proportional-type controller like the Tekonsha Prodigy P2, part # 90885. A proportional controller has an internal sensor that can detect how quickly and at what intensity the tow vehicle is braking, and will then send the appropriate amount of...
    view full answer...

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