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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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Tekonsha Converter Custom Fit Vehicle Wiring - 118355
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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. Includes tail light converter. 1-833-496-1390 to order Tekonsha custom fit vehicle wiring part number 118355 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 (90)
  • Q & A (0)
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  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • 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. Includes tail light converter.


  • 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 rear cargo area
    • Plug in T-connector
  • Includes a tail light converter to ensure that your vehicle's wiring matches that of your trailer
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


  • Maximum amperage:
    • Stop/turn lights: 2.1 amps per circuit
    • Tail lights: 4 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 interior trim panel in your rear cargo area. You will need to remove the storage compartment door or trim panel to access the harness.

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.

Tail Light Converter

A tail light converter 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. The tail light converter combines 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.

118355 Tow Ready T-1 T-Connector - 4 Wire

Item # 118355

Installation Details 118355 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 - 118355

Average Customer Rating:  4.9 out of 5 stars   (90 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. Includes tail light converter.


Easiest plug n play I've ever dealt with literally had it installed in 15 mins. Don't look beyond this one, fantastic!!!! E-trailer is outstanding had it in my mail box in 3 days... that is stellar to me in today's world as we know it.....


Quick service! Item arrived 1 day earlier than the expected delivery date. I recommend Etrailer for your trailering needs. Excellent Experience!

2002 Pontiac Montana

The wiring harness I purchased was extremely easy to install and works great. The hardest part was getting the ground screw in because I did not have the right tools for my drill gun. Went across the street to hardware store and bought it. It probably took me 15 minutes to get the whole project done and lights tested. I would recommend this product to anybody who needs to wire there vehicle. On a side note I did buy dielectric grease just to make sure I got good electrical connection

2004 Pontiac Montana

Connected right up! Had to pull the little storage tray up to get to a good spot for the grounding wire. Works like it should!


Hello, I am a 61 year old man,and I have always had trailers since I was a young man.My family has always enjoyed camping in nearby Andirondaks and also on lake Ontario.I am very mechanical and can fix almost anything.Well I always have hard-wiredmy trailer lights myself up until now,and grumbeled about hooking a one bulb system (trailer) into atwo bulb system (car).It has always taken at least hour or two figure out how to wire in converter the proper way. With your system I removed three screws, pulled back side-panel reached in and plugged in the pig-tail conector, anduse self tapping screw to secure ground to body,and shoved convertor and extra wire behind panel,replaced the three screws,plugged in trailer and everything worked perfectly.This is by far easest set-up I have ever done, and will recomend it to all my freinds,Thanks Cal Buerman

still working great,thanks
Cal B - 10/21/2015

2012 Chevrolet Volt

Very easy. Did plug and ground through the 12 volt accessory plug door. Pry out the black plastic panel that the 12 volt female plug is on and then unplug its wiring. Adhere to the directions, being careful where you drill the 3/32 hole for the ground wire. I did the ground wire first. I drilled the hole for the grounding screw with a Dremel like tool. It was then a snap to plug in the white plug and stick the black box to a flat spot to the right of the white plug. I then let the trailer plug slide down in back of the plastic side wall and fished it out with my fingers when it reached the floor of the back deck. The air conditioning fan housing looked like it would be annoying, but I found that it was not a problem in doing the work. I did everything through the 12 volts plug opening. There is no need to pry open any other panels. I am very happy with the product and


Customer service was great and the product fit perfect as descibed online. I would definitely use your company again and again infact i'll purchasing another hitch for my other work van. I appreciate you following up a year later. If you have any type of sticker, i would not hesitate to put it on the hitch or any product to advertise for you because when your company does good then you can continue to support your customes with great service and products


Hidden Hitch excelent product EZ to install. Took three hours. Hardest part was cleaning outhe welded nuts on frame.Wiring Harness was actually to EZ to do. Spent some time trying to figure where male connector went. Delivery was unbelievabley fast. Didnot expect it for a couple days. Thanks loads for all the backup help to the girls to get my account in order and quick delivery.

2000 Pontiac Montana

The product was plug and play; it doesn't get any easier than that. That said, I had a heck of a time finding the electrical connector on a 2000 Pontiac Montana with the rear air handler/AC unit.
I finally found mine WAY behind the AC unit- I had to fish it out with a pair of extended needle nose pliers, and there wasn't enough spare wiring to get it past finger reach. You do not need to remove the air compressor/12V outlet panel. I utilized the existing ground at the site of the wiring, the provided eyelet on the ground fit without modification.

TL:DR- Look BEHIND the A/C unit!


Jacked up rear end, 30 minutes Hitch was on . Jack down 10 minutes later wiring was done. How simple was that??? etrailer is a great supplier. Doug

2004 Chevrolet Venture

Quick and easy to hook up, worked perfectly. The best part was the video that showed where the connector is hidden in the car. I NEVER would have found it!

They are all working great, thanks. No complaints.
JR - 07/20/2015


I have had to chase tail/brake light wiring to hook up a trailer more times than I'd care to remember.
This 'plug and go' harness was installed in 5 mins and worked like a charm.
I just watched their video and was up and ready in no time.

Pontiac Montana

Easier than AdvertisedI was expecting a challenge after researching the installation procedure for this wiring harness for my Montana EXT AWD. Was pleasantly surprised that the factory connector was accessible through the panel by simply removing the air compressor panel. Needed a washer for the ground screw as it would not snug up tight enough to hold the terminal. Just make sure the terminal cannot be turned by hand before replacing the rear interior panel.

2004 Chevrolet Venture

Most of my remarks are on the Hidden Hitch review. This connector was another quality product. The on-site video showed me EXACTLY what I would find and where. It was a simple "plug-and-play". Lights work perfect, was enough cable, all the parts were there. Simple. You guys at "etrailer" must actually install these products because everything was right. I can't say enough about how helpful the installation video was!!!!!!!!!!!! (2004 Chevy Venture)


Easy plug and play. Worked as it should.

great, works as it should
Chris - 03/08/2021

2003 Chevrolet Venture

Once I figured out what I was doing on my 2003 Venture, I had absolutely no problem installing this harness. The problem was not with the harness, it was with the vehicle. Although the instructions where very good, I had to improvise. Instead of removing the side panel as recommended, I removed the top tray and it worked out better with less work. the support from etrailer was great.

2004 Pontiac Montana

Overall, very happy with this product. The screw tab on the black box could stick out further from the body of the box, but I was able to make it work. Everything else worked as the instructions said, and the tail-lights and turn signals on the trailer lit up.


The product, instructions and your service were all GREAT!
Installing the wiring was a piece of cake, and only took about fifteen minutes, with most of that time used to undo a poor wiring job a previous owner of my van had done.
The wiring works great, so now I can hook up my boat trailer, and go do some fishing.
The next time I need anything auto related. I'll contact etrailer.
Thanks again, Dave

2004 Oldsmobile Silhouette

Nice to plug and play to connect wiring. Unfortunately no good opening inside panel to run wire to back. Did not want to drill a hole inside, so wiring is on top of back door weatherstripping. Might need 2 trim tabs with 1" heads on them if you remove the sill on the back door to open the side panel.


Best customer service have had in a long long time ,great product , fast delivery, easy to install , had a little trouble with wiring but after talking to Bill found it was nec to remove part of rear a/c housing to find connector plug, after that everything was a breeze.

Thanks for great service.


2001 Pontiac Montana

The wiring harness is easy to instal and a high quality product.
Also you can not beat the price.

2002 Pontiac Montana

I ordered this for my montana after trying to wire up a 4 pin plug just to realize that I need a different setup. I order this and followed the instructions that came with it. I had this installed in less then 30 minutes and it worked perfectly. Everything worked. I will definitely look here for more things first next time.

2000 Oldsmobile Silhouette

Good product, One note on a 2000 olds silhouette with the air compressor you have to cut the plugs off and attach it to the factory harness you should have with your van, at least according to the olds dealer.


From the instructions to the final product was easy to install and use. I was not sure of what I was doing, but after getting started everything went just as planned.


This hitch was extremely well built, and fit beautifully.

The written instructions leave a lot to be desired, but the video explained it all.

I forgot to take pictures, but it's installed, and I'm happy.

The written instructions on the light kit wern't the greatest either, but the actual parts worked very well.

Show More Reviews

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

  • Does Trailer Wiring for 2004 Pontiac Montana Carry Turn Signals and Stop Lights
    The trailer wiring harness part # 118355 which is a confirmed fit for your 2004 Pontiac Montana will provide your trailer wiring with signal needed to activate the turn signals, brake lights, and running lights. I attached an install video for you to check out as well.
    view full answer...
  • Cant Find T-One Connector Plug on my 2003 Chevrolet Venture to Install Trailer Wiring 118355
    Since the part # 118355 can fit a few different vehicles with differing setups you will need to check a few places to find the connector you need. First thing I would recommend is checking out the install video I attached to the right that shows this harness being installed on a 2003 Chevy Venture just like yours. Also, some vehicles will only have one connector. Some of the vehicle options have another connector plugged in series with the taillight connector plug, and the second plug...
    view full answer...
  • Where is the Trailer Wiring Connection Location on a 2000 Chevy Venture
    On a 2000 Chevy Venture you will need to pull up the threshold panel in the cargo area so you can pull back the panel on the driver side. The wiring harness should be nearer the end of the vehicle. It can be either a single connector with nothing plugged into it or two connectors connected together. In either case it could be hiding behind another wire bundle or even taped up with another bundle so you cannot see it. I have included links to a couple of videos showing typical installations...
    view full answer...
  • Location of Factory Connection Point for Trailer Wiring Harness on a 2003 Chevy Venture
    The plug will be there on a 2003. It is just that we have not had a 2003 Venture in to make a video but we have had a 2002 and 2004. To find the factory harness you will need to pull up the threshold panel in the cargo area so you can pull back the panel on the driver side. The wiring harness should be nearer the end of the vehicle. It can be either a single connector with nothing plugged into it or two connectors connected together. It can also be located behind an air conditioning unit...
    view full answer...
  • Accessing the Plug for a T-One Connector on a 2000 Chevy Venture
    I am sorry to hear that you are having trouble with your T-connector, item # 118355. Most customers assume that the plug is directly behind the drivers side panel in the rear. But the plug is usually behind the air conditioning unit that is directly behind the panel the air conditioning unit will have to be pulled away to access the plug. I hope this helps. Let me know if you need more info.
    view full answer...
  • T-1 Vehicle Wiring Harness Part # 118355 for a 1999 Chevy Venture
    I am assuming you are needing a T-1 connector, part # 118355. The connection point is behind the trim panel on the drivers side, just behind the taillights. I will provide a link below to the installation instructions, which will explain the whole installation procedure. We also have an installation video showing the install on a 2002 Venture. The procedure would be identical to that of your 1999 model.
    view full answer...
  • 4 Pole Trailer Connector on a 2004 Chevy Venture
    I'm sorry you found the instructions with your wiring harness lacking. The 4-pole trailer connector is meant to be stowed in the rear cargo area when not in use. When you need to tow, run the 4 way out the door, and close the hatch on it. The weatherstripping provides enough cushion to prevent damage to the wires. Just be sure to keep the wire away from the latch, which WILL damage the wire. This arrangement protects the trailer connector from moisture, corrosion and damage. I use this...
    view full answer...
  • 2000 Pontiac Montana With Insufficient Voltage for Turn Signal/Brake Lights at Trailer Connector
    It sounds like you have the ground taken care of. Are you using a tail light converter? Part # 118355 is the converter offered for your vehicle. The factory does provide the port for the towing wiring, but a converter is still needed. If you have a converter installed already, I would recommend testing the wires on the input side of the converter. You should have 12-volts entering and exiting the converter while each function is activated.
    view full answer...
  • Will T-One Trailer Wiring Harness, # 118355, Work with a 2001 Pontiac Montana with Air Compressor
    According to Tow Ready, on some vehicles with air compressors, the plugs will not be accessible through the storage compartment. You would need to pull back the interior trim panels to access the connectors. So the T-One Vehicle Wiring Harness with 4 Pole Trailer Connector, # 118355, is the correct harness for your 2001 Pontiac Montana. I have included a link to the installation instructions below. I do not recommend splicing the brake light wire into the turn signal wire as it would cause...
    view full answer...
  • Troubleshoot Trailer Wiring Lights Not Active Installed T-One Kit # 118355 on 2002 Chevy Venture
    The T-One trailer wiring harness part # 118355 is a confirmed fit for your 2002 Chevy Venture whether it would have the towing package or not. The connector you used to plug this kit into should be active either way. It sounds like you may have a blown fuse or relay under the hood of your van which is causing the power not to be present.
    view full answer...
  • Wiring Harness Fit for 2003 Oldsmobile Silhouette
    I have a wiring harness for you, however the Draw-Tite # 24721 does not have a wiring harness included. I would use this Custom Fit Wiring Harness from Tow Ready # 118355. This harness will plug into your vehicle's existing wiring and comes with a 4-way flat connector. I have attached an installation video of this wiring harness on a 2003 Chevrolet Venture for you, it will be similar to your Silhouette.
    view full answer...
  • Troubleshooting Trailer Wiring On 2004 Pontiac Montana
    The first thing I would recommend is to try connecting the trailer to another vehicle to see if the same problem exists. If not then the problem is going to be found on the Montana. If the wiring harness is hard-wired you will want to check the ground to make sure it is corrosion free and attached to a clean bare metal surface. Check the connector to make sure there are no signs of corrosion or damage to any of the pins and correct as needed. Since the trailer harnesses we offer for...
    view full answer...
  • Installing Tow Ready Trailer Wiring Harness # 118355 on 2001 Oldsmobile Silhouette w/ OEM Compressor
    The Tow Ready taillight converter, part # 118355 is designed to intercept the signals going to the taillight assemblies by plugging inline with the connection shown at the :35 second mark in the video I've linked you to. I spoke with my contact at Tow Ready, who tells me that on vehicles that were equipped with the compressor, the connectors you're looking for could be closer to the door jamb or in front of the compressor, closer toward the front of the vehicle. You might need to pull...
    view full answer...
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  • Is Converter Needed for Installing Trailer Wiring Connector on 2003 Chevy Venture
    It looks like your 2003 Chevy Venture has a separate wiring system, which means the brake and turn signals are sent along separate wires. With this type of system, a converter is required and simply hardwiring the vehicle wires to a 7-Way adapter without one will not allow the trailer light functions to work properly. The T-One Vehicle Wiring Harness # 118355 referenced in your question does include the necessary converter. The plug-in locations should be behind the driver side trim panel...
    view full answer...
  • T-One Vehicle Wiring Harness on 1998 Oldsmobile Silhouette Shorting Out
    To run down a short in a wire you will need to use a circuit tester, item # 40376 if you need one, to test the wiring and find the short. The place I would start is on the vehicle side of the converter. Check each wire there, with a helper to turn on turn signals and step on the brakes, and be sure that each circuit is functioning properly. While you are behind the taillights make sure the ground wire is attached to a good grounding point. Next I would test the wiring coming out of the...
    view full answer...
  • Troubleshooting Tow Ready T-One Vehicle Wiring Harness, # 118355, on 1998 Pontiac Trans Sport Van
    The 1998 Pontiac Transport has a 3-wire system with a converter, so there is no splicing needed. The Tow Ready T-One Vehicle Wiring Harness with 4 Pole Trailer Connector, # 118355, that you have is the correct harness. You will need to use a circuit tester like part # 40376, and test each wire going into the converter as its function is activated. With somebody to turn on the turn signals and step on the brakes, test each wire to see that it is working properly. Also make sure the ground...
    view full answer...
  • Trailer Right Turn Signal Not Working When Connected To 2004 Chevy Venture
    Since the trailer lights are working when connected to the 2008 Dodge Grand Caravan, it sounds as though the converter that is in your 2004 Chevy Venture trailer wiring harness might be damaged. You will need to use a circuit tester like part # 40376, and check the wire for the right turn signal that is going into the converter box. If it has power going into the box, then you will need to check the wire for the right turn signal coming out of the converter box. If there is no power...
    view full answer...
  • Installed Tow Ready Wiring Harness, # 118355, And The Left Brake Light Is Constantly On
    Sounds like the wiring on your trailer might not be connected properly. You can use a circuit tester like the, # 40376, and test the wire connections on your trailer. The brown wire is for trailers taillights and should be connected to the vehicles taillight. The white wire is the ground and you will want to check and make sure that it has a good, clean ground connection or if your trailer lights are grounded by the mounting studs that it is grounded properly. The yellow wire is for the...
    view full answer...
  • Tow Ready Trailer Wiring Recommendation for a 2003 Chevy Venture
    For your 2003 Chevy Venture it is recommended that you use a Tow Ready Custom Fit Vehicle Wiring # 118355. This unit will not require any wire cutting or splicing to install on your vehicle. It will be a simple plug and play installation. I attached installation instructions and an installation video of this product for you to check out also. The Tow Ready Wiring Harness # 119178 that you referenced could be used on your vehicle but it would require you hard-wiring the unit into the tail...
    view full answer...
  • Trailer Lights Not Working on a Camper Towed by a 2002 Oldsmobile Silhouette
    A fuse blowing indicates to me that there is a short. If it happens when you connect the trailer to test the lights then that would indicate a problem on the trailer side. Lets first look at the wiring harness on the van. Make sure the ground wire is attached to a clean metal surface. Moving the ground might help. When you plug in the 4-Way to the adapter, # 30717, make sure the connection is good and tight. You must have the ground wire from the adapter also attached to the vehicle frame. This...
    view full answer...
    Image 1 for Image 2 for
  • Connecting the Red Brake Controller Wire to the Brake Switch on a 2012 Chevy Equinox
    Typically on Chevy vehicles like your 2012 Equinox, the brake switch wire you need will be light blue with a white stripe. However, you will need to test with a circuit tester like # 40376 if needed to find the correct wire. The wire you need will show a signal on the circuit tester only when the brake pedal is pressed. If you find any wire that also shows a signal when the running lights or turn signals are on it is not the correct wire.
    view full answer...
  • Will Curt Class III Trailer Hitch Fit Short Wheelbase 2000 Pontiac Montana?
    Yes, the Curt Class III Trailer Hitch, # 13344, will fit your 2000 Pontiac Montana with a short wheelbase. This hitch would actually be my recommendation for you. I usually prefer Curt trailer hitches because I know they like to be a little liberal with their powder coating and in this case, it has the highest weight capacities of any hitch for your van so it has plenty of built-in safety margin. All of the wiring harnesses for your vehicle are basically the same thing, but built by three...
    view full answer...
  • Trailer Running Lights Not Working and Other Lights are Dim on Trailer Towed by 2001 Pontiac Montana
    Since the trailer lights work fine on a different vehicle, I would start looking at the trailer connector on the 2001 Pontiac Montana. If there is any corrosion build up inside the connector then that can cause a poor connection and cause the issue you are describing. If the vehicle side connector is cleaned out, you can go on to testing the converter itself. Start by testing the wiring going into the converter from the vehicle using a circuit tester like # 40376 if needed. If the wiring...
    view full answer...
  • Difference Between Hopkins # HM41365 and Tow Ready # 118355 Wiring Harness for 2003 Olds Slihouette
    Both the Hopkins # HM41365 and the Tow Ready # 118355 would be correct for your Silhouette. Both wiring harnesses have the same capacity, preform the same function and would install in the same manner. Either harness would work well for you. The price differential reflects our cost on each item, and does not mean that one harness is better or includes different features than the other. To see install details for each item and an install video , click on the provided links. The video...
    view full answer...

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