T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
(420 reviews)
Price: $57.98
In Stock
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector
Item # 118521
Our Price: $57.98
Will this fit?
To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
In Stock
- All Info
- Reviews (420)
- Q & A (0)
- Photos
Tekonsha Custom Fit Vehicle Wiring - 118521
- 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 rear cargo area
- Plug in T-connector
- 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 behind the driver's-side interior trim panel in your rear cargo area. Once you've plugged in the T-connector, open your fuse box and locate the fuse positions indicated in the instructions. Then insert the included fuses.
Once installation is complete, the 4-way flat connector can be stored in an out of the way area of the cargo area of your vehicle when not in use.
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.
118521 Tow Ready T-1 T-Connector - 4 Wire - Modu-Lite
Installation Details
This Product Fits The Following Vehicles
- 2011 - 2017 Honda Odyssey
- 2011 - 2017 Honda Odyssey
California residents: click here
Customer Satisfaction Score:
97% were satisfied with this product
3% of customers were not satisfied
- Wrong item was ordered
- Did not arrive in time
- Product did not meet expectations
Customer Reviews
T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118521
Average Customer Rating: 4.8 out of 5 stars (420 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: Roger 08/14/2023
Honda Odyssey
A year down the road and the wiring harness is still working great.
This was an easy install. I was selling an other Honda Odyssey van and was able to switch the hitch, but the wiring harnesses were not compatible. The local trailer company wanted $150 to install a new wiring harness..... this was easy an install and I clearly recall spending more time trying to find one of the mini-sized fuses I dropped, than installing the wire harness.
Etrailer.com is my go-to-place for any trailer needs... and the videos are spot on confidence builders...
by: Richard 05/09/2023
This wiring harness was easy to install. The instructions were clear, but to be honest, I found the etrailer staff's installation video for this harness to be a great aid for the install. I've installed a few harnesses bought from etrailer and all of their install videos have been spot on. I have not had any problems with this harness either. It was well made and should last a very long time.
by: Bob06/07/2023
It would have been nice if the hitch would have included a tap. It was such an unusual size tap that none of the stores in our area had one so I had to special order it. I mounted the hitch ok, but I ended up taking it to a store to get the wiring done. They told me that the directions that came with the wiring kit was incorrect and that is why I had trouble. Other than that the delivery and service was great.
by: Franklin08/21/2022
2017 Honda Odyssey
Everything came very quickly and was 100% compatible. Using the video for the hitch installation was a huge time save. First time installing a hitch and wiring and had it done in under 2 hours. Installation on 2017 Honda Odyssey and can confirm the 2016 model tutorial is identical to my 2017 model.
by: Christopher 07/01/2023
Delivered early, took longer to find my tools then to install. My local uhaul and hitch installer wanted $110.00 to $200.00 for what took less than 15 minutes. I would recommend Hanna at etrailer for all your trailer needs.
by: Daniel 07/11/2023
2016 Honda Odyssey
Really easy to install on a 2016 Honda Odyssey. Remove back panel and plug it in! Etrailer has some great videos too for help with the installation.
by: Jim H.12/24/2013
2014 Honda Odyssey
The product worked as advertised, but the installation did not. I have a 2014 Honda Odyssey Touring Elite. This model has the HondaVac, a 12 volt power plug, and a subwoofer on the panel that must be removed to follow the instructions. Unfortunately, the video and paper instructions show a base model and do not explain how to remove these optional items. I'm fairly mechanical and could not figure out how to remove them without damaging something. I only tow once or twice per year, so I decided on a temporary solution where I plug in the harness and ground it to one of the threshold plate cargo net hooks. Speaking of those, I found it almost impossible not to mar the plastic, even with a washcloth between them and the wrench. You may want to try a strap wrench or rubber padded wrench. I towed a u-haul cargo trailer with this setup for three hours on a mix of country, subdivision, and interstate roads with no issues. My only concern was the quality of the grounding connection, but the bolt and grounding tab appear to touch the frame.
Comments
I just got off the phone with my contact at Tow Ready. I will put him in touch with you to get the harness straightened out.
-- 
Patrick B - 12/27/2013No change after a year. My temporary solution remains sufficient for my once a year towing needs. If someone owns an Odyssey with the HondaVac and wants a clean trailer hitch and lighting install, I recommend getting it done through your Honda dealer. If you have a lower trim level without the HondaVac this kit is a cheaper DIY alternative.
Jim H - 12/24/2014by: Shelley07/11/2023
Easy to install, clear directions, worked properly when tested. Replacing a Curt harness, which has reliably failed every 2-3 years.
by: Pete 01/05/2023
Honda Odyssey
I purchased a harness for a used Honda Odyssey that we use as a people and trailer hauler. It took me about 20 minutes to install the wiring harness as it was plug and play. The installation instructions on the video were excellent.
Very happy with the product and instructions. Strongly recommend
by: Dirk10/02/2019
This Tekonsha T-one harness with control module really works great, is super easy to install and you can't beat the price at etrailer.
But because of a problem I had with water ingress into the control box, I wanted to share with potential buyers a different mounting solution that will avoid what happened to me.
I initially installed one of these 3 years ago in our 2013 Odyssey along with a new vehicle side connector. It worked great until last fall when our trailer lights started doing strange things. Thinking this was a ground fault I disassembled the connector and cleaned all the contacts, but it didn't solve the problem. Then I installed a brand new connector, but I still had the same problem.
Then I retraced the T-one harness and found the control module full of water and the circuit board fried of course. I installed it in a way that it was hanging down into the cavity behind the interior panel (much like another customer here shows it in his photos). Somehow, water was able to find it's way in it.
Now I installed a new Tekonsha T-one harness and everything is working great again, but I chose a different location for the control box. I used double sided tape to glue it onto the upper compartment of the interior panel. This way it will hopefully not be exposed to any water that might drip down. It is also angled slightly upward, so that any moisture should drip off instead of running into it.
The harness is long enough to allow for this with the exception of the ground cable. But a 12" extension will do the trick. I hope the photos are clear enough to show all this.
Hopefully someone finds this information useful.
by: Justin F07/17/2014
2013 Honda Odyssey
Great service and good product. This was embarrassingly easy to install. Took me about 45 minutes. Car is pre-drilled and ready to accept the hitch
Comments
I like it a lot. I have recommended it to two other people who have also now bought hitches and light assemblies from you. Thank you
Justin F - 07/20/2015by: Ken 03/08/2023
Excellent product except the pigtail connector to trailer should have been a foot longer the ground wire should have been a half a foot longer
by: Gilbert06/13/2019
2012 Honda Odyssey
The customer service was great! Both Teresa J and Odelia were very kind and helpful. They seemed to to be in good spirits and enjoy their jobs. They helped me with my order and my concerns. The draw tite hitch was easy to put on. You will need help lifting it in place since it is heavy. The video on how to install it on a 2012 Honda Odyssey was very helpful although I did need to unscrew 3 additional screws holding the bottom cover to the mud flap. I was a little concerned to find that the hitch had a few scratches and scrapes on a corner. I called and Odelia had advised me that it is not uncommon since the products arrive to their location unpackaged and piled on one another. I decided to keep it and just paint the corner with rustolium spray paint. Overall the product looks good and seems to be of good quality.
The wiring harness was easy to put on. The video was spot on.
The videos for both products are extremely helpful.
by: Jameson09/05/2022
What makes this product so great are two things. First, the quality. The fit and finish is excellent. And second, the service and instruction provided made the installation go so smoothly. I ordered a hitch and wiring harness for a 2016 Honda Odyssey. I was provided with video content; instructions for the installation and to my surprise it was for a 2016 Honda Odyssey. So often I’m left watching videos for a range of model years and I’m left adapting the instructions to my specific vehicle, but not in this case. And this was true for both videos; the hitch and the wiring harness.
Great product and service! I highly recommend etrailer.
by: TS09/07/2023
Easy to install. Delivery was fast and the transaction went smoothly
by: Allan P.08/16/2017
2015 Honda Odyssey
This T-One Vehicle Wiring Harness comes complete with all you need to do a proper professional job, it is top Quality and very easy to install.
by: Ernie 04/20/2021
Etrailer has made this process so incredibly easy, with vehicle specific applications and videos made for that particular vehicle. I have bought two hitches and wiring harness for my vehicles and install was a breeze. Thanks Etrailer
Comments
One year later and ZERO issues. etrailer is my go to trailer trailer parts source!! FIVE STARS
Ernie - 04/25/2022by: Paul 09/09/2023
good product easy install
by: Jacob05/15/2022
Easy install.
Comments
Everything is working just as it should!
Jacob - 05/16/2023by: Dennis01/04/2023
I Always buy my hitches from you, and always have great service.
by: Edgar R.02/20/2015
2012 Honda Odyssey
Great product easy to install kind of fun!
Used references from your video to install on my 2012 Odyssey but noticed it says to place one of the 7.5 fuses in location #10 it actually goes in #11. Other than that very satisfied. Thanks "again".
by: Ryan08/19/2022
Great product, easy to install. Took a little bit to get the hitch aligned square to get all the bolts in but this user had zero prior mechanical experience. I’d 100% refer someone else to this website
by: John05/13/2023
4 star. The muffler had to be dropped to install. Shipped fast - product looked great. There were some holes in the box but the shippers as much at fault.
by: Mike08/20/2013
2013 Honda Odyssey
Video is great for installing, instructions in package, too. Product picture of fuse block does not match 2013 Odyssey for fuse amps. Overall it was an easy install and well detailed. Thanks.
by: Elden H.05/29/2016
2012 Honda Odyssey
I owned a 2007 Honda Odyssey and purchased a trailer hitch and wiring harness from etrailer. I later replaced the 2007 with a 2012 Honda Odyssey and found that the 2007 trailer hitch would fit the 2012. I then ordered a wiring harness from etrailer for the 2012. In both purchases from etrailer, not only did I get good service, but also a great product, and as a bonus a great pricing. Both the hitch and wiring harnesses came with clear installation instructions with the install being easy to do. Their product and fast service was great and would rate them a 12 out of 10... thanks etrailer!!!
Comments
Great produce. It was easy to install, great instruction, and after year it is working great. I have never been disappointed with their products...great gquality and service.
Elden H - 05/29/201725
420
Show More Reviews
See what our Experts say about this Tekonsha Custom Fit Vehicle Wiring
- Troubleshooting Trailer Right Stop/Turn Signal not Functioning on a 2011 Honda Odyssey 4-WayThe first place I would check is the rear fuse panel on your 2011 Honda Odyssey. It sounds like you blew a fuse so checking the condition of the fuses required to install the Tow Ready Wiring Harness part # 118521 is a logical solution. You will want to check the condition of the 10 amp fuse that's in the number 8 position of the rear fuse box as well as the 7.5 amp fuses in the number 2 and 11 position. Fast forward to the 2:00 minute mark of the video I attached to see where these fuses...
view full answer... - Trailer Hazard Fuse Keeps Blowing on 2013 Honda Odyssey Using Trailer Wiring Harness 118251There could be a short on the trailer that is causing the fuse on your 2013 Honda Odyssey to keep blowing. You will want to inspect the trailer wiring and look for any pinched or sandwiched wires, frayed wires touching bare metal, or corrosion at connection points and fix as needed. If the fuse is blowing without the trailer connected then there may be a bent or broken pin on the wiring harness connectors or where it plugs into the van. A bent or broken pin on the harness would mean...
view full answer... - Running Light Circuit on TowReady T-One Vehicle Wiring Harness # 118521 Shuts DownThank you for your purchase from etrailer. The problem you describe of just the running light circuit on your T-One Wiring Harness # 118521 going dead after a short period of use could have two causes. Either the harness is damaged internally or your trailer's running lights are drawing too much current (in excess of the unit's 7.5-amp capacity for this circuit). This 7.5-amp rating is fairly high, but still it could be the reason. Since the unit appears to reset itself once you turn...
view full answer... - Will Installing a Trailer Wiring Harness on a 2012 Honda Odyssey Void the WarrantyThere is a law called the Magnussen-Moss warranty act that states, in part, that if you install an aftermarket part on your car then it will not void the warranty unless that part caused the problem. So installing the trailer wiring harness, # 118521, will not void the warranty. I have included a link to the installation details and a link to a video showing a typical installation.
view full answer...
- What is the Amperage Rating for Trailer Wiring Harness 118521 for a 2012 Honda OdysseyTrailer wiring harness # 118521 is rated for 4.2 amps per side for brake lights and turn signals and 7.5 amps total for running lights. Since your trailer has exterior lights you will need to determine the amperage draw of all the lights on the running light circuit. The amperage draw should be on the lights somewhere. If the amperage draw exceeds the capacity of the harness I recommend switching everything over to LED lights. LEDs use a fraction of the power that incandescents use. They...
view full answer... - Trailer Wiring Harness Recommendation for a 2015 Honda OdysseyYes, I checked with Tow Ready and the wiring harness part # 118521 that you referenced has been confirmed to fit the 2015 Honda Odyssey so it would work well for you. I attached an install video for this harness for you to check out as well.
view full answer... - Troubleshooting Trailer Blinkers/Stop Lights that Don't Work after Install of Harness # 118521It sounds like the issue you are having is fuse related. We had a customer with a 2012 Odyssey just like yours leave us a comment saying that they had to use a different fuse location than what the installation instructions indicate to get all of the functions of the harness to work. They said that the 2012 model required the 7.5A fuse to be placed in the small trailer slot vs the trailer back slot as indicated in the instructions. Another customer said they had to put a fuse in the trailer...
view full answer... - Subwoofer and HondaVac Not Functioning after Trailer Wiring Harness Install on a 2014 Honda OdysseyEither the sub and Hondavac of your 2014 Honda Odyssey got unplugged during the install and weren't plugged back in properly, or there was a short on the trailer harness that blew the fuses of the two since they are close to where the trailer harness plugs in. Most likely the problem is fuse related though. Check the fuse panel near the harness in the back of the vehicle and then also check the other fuse panels of the vehicle. If this happened after you towed your trailer then most likely...
view full answer... - Trailer Wiring Harness Recommendation for a 2014 Honda OdysseyFor your 2014 Honda Odyssey I would recommend the Tow Ready harness part # 118521 as it is a confirmed fit and because we have much better luck with the Tow Ready harnesses compared to the Curt ones. I attached an install video for you to check out as well. I would strongly recommend you unplug the trailer wiring before backing into the water though as water and electricity don't mix well.
view full answer... - Can Tekonsha Trailer Wiring Harness for 2012 Honda Odyssey install on Vehicle with Backup SensorsIf the port for the Tekonsha harness part # 118521 is open on your 2012 Honda Odyssey just go ahead and install the harness in it without worrying about the back up sensors and you'd be totally fine. I attached an install video for this harness on a similar 2012 Odyssey as yours for you to check out as well.
view full answer... - How to Turn Off Back Up Sensors on 2014 Honda OdysseyAs for the installation of the T-One Vehicle Wiring Harness # 118521 , if there is no plug already in the 14 pin socket that's ok. You'll still want to plug the harness into that 14 pin plug and just leave the other end unplugged. When it comes to your parking sensors, the Honda Odyssey parking sensors are only active when the car is traveling less than 10 mph. There are four sensors located on your car. The sensors at the corners of your vehicle have a range of 24 inches. The sensors...
view full answer... - How To Install Trailer Wiring Harness on 2016 Honda Odyssey SE with Rear Vacuum Cleaner OptionAlthough Tow Ready hasn't done an install on an Odyssey that's equipped with the HondaVac option, I was able to obtain some very welcome feedback from one of our Customers who recently installed the # 118521 on his 2015 Odyssey SE with the integrated vacuum cleaner. Below is the information he kindly provided: The procedure follows the same install steps provided in video, the only difference is the routing of the wires and the location of the control box. - unscrew the HondVac hose -...
view full answer...
- Troubleshooting Trailer Wiring Harness that Lights Up Tow Vehicle Taillights When ConnectedWhat you described sounds exactly like a shorted out converter box for the part # 118521. You will need to replace the converter, but before you do that you will want to check the wiring of the trailer for shorts as that is what most likely caused the box to short out. When a trailer sits for an extended period of time (typically in winter), corrosion on the trailer connector has a more likely chance of showing up which can cause shorts. I would not recommend reconnecting you trailer...
view full answer... - Where to Route the 4-Way From the Tow Ready Wiring Harness on a 2011 Honda OdysseyI spoke with my contact at Tow Ready and he informed me that you can run the Tow Ready Custom Fit Vehicle Wiring # 118521 either through a grommet in the floorboards to the outside of your vehicle, or you could keep it inside the cargo area when not in use and then run the 4-way out the door when you need it. I attached installation instructions for this product for you to check out also.
view full answer... - Trailer Wiring Harness Recommendation for 2015 Honda OdysseyThe T-One brand in general is more reliable than the Curt brand so for your 2015 Honda Odyssey I would go with the part # 118521 over the Curt # C56118 that you also mentioned. The T-One has a higher amperage rating which means it will be less likely to short out than the Curt. As far as fit I can't seem to find any issues where the harness did not want to fit properly.
view full answer... - Trailer Wiring Harness Recommendation for 2016 Honda OdysseyFor your 2016 Honda Odyssey the best trailer wiring harness we offer is the Tekonsha part # 118521 which is a confirmed fit. Of all the brands of trailer wiring harnesses this is the one that is the most reliable we have found. I attached an install video that shows this installing on a 2016 Odyssey just like yours as well.
view full answer... - Where Does Trailer Wiring Harness # 118521 Install on 2014 Honda OdysseyThe picture you submitted shows the correct port to plug in the part # 118521 on your 2014 Honda Odyssey. It's the lower port on the left that is larger than the rest.
view full answer...
- Why Does Trailer Wiring for 2015 Honda Odyssey Route Through Rear DoorHaving the 4-way run out of the back hatch is actually the preferred method although it seems like it wouldn't be. Having the 4-way stored inside the cab of the keeps it protected from rain and moisture to prevent corrosion and keeps it protected from damage to the wiring or connector by rocks or debris that might be on the highway. You can run the wire through the vehicle if you wish but just keep in mind that this does take more time and you may end up needing additional wire because...
view full answer... - Troubleshooting Trailer Running Light Circuit Not Functioning on 2014 Honda OdysseySounds like the trailer wiring issue you have for your 2014 Honda Odyssey is related to the tow package wiring setup of the vehicle. What I would recommend first is to check under the hood of your vehicle for the trailer running light circuit fuse and replace if needed as it sounds like possibly a blown fuse. We do have the part # 118521 though which will replace the converter box and wiring if the problem happens to be there insted. If the fuse you checked looks good and you still have...
view full answer... - Where Does Other Plug Go on T-One Vehicle Wiring Harness for 2012 Honda OdysseyIn regards to the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118521 which is a fit for a 2012 Honda Odyssey, there are two white rectangular connectors on the main harness. The connector with multiple wires goes directly to the fuse panel. The connector with one wire only gets hooked up if there was a connector in the slot that the connector with multiple wires was just plugged into. I have attached a video below which explains this a bit better at about the...
view full answer... - Trailer Stop and Turn Signals Stop Working On 2012 Honda OdysseyIt sounds like the converter is defective on the wiring harness. Unfortunately, this means the entire wiring harness will need to be replaced. The converters can fail over time on their own but the most common failure is caused by the converter not being secured enough and the wires inside coming loose from the circuit board. For replacement, I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118521 which we have found to be more reliable than other manufactur...
view full answer... - Trailer Wiring installation For My 2012 Hyundai Santa FeThe T-One Vehicle Wiring Harness, part # 118415, will plug inline with the tail light wiring behind each tail light. This wiring harness does not require a trailer prep package to install. The # 118415 is a plug and play wiring harness and does not require any splicing of wiring. The 4-way trailer plug will be stored in the rear cargo area of your Santa Fe when it is not being used. When you are using the 4-way trailer plug, you can just feed it over the rear door weather stripping. I...
view full answer... - 4 to 5-Pole Trailer Connector Adapter # 20036 Needed for Boat Trailer Towed by 2012 Honda OdysseyWe have exactly what you are looking for. The 4 to 5-Pole Adapter, part # 20036 would plug into the connector on your boat trailer. The other end of the harness plugs into your existing 4-pole with an additional lead that is tapped into the reverse light circuit of your Odyssey. When the Odyssey is shifted into reverse the signal is sent to the reverse lock-out in your trailer coupler, releasing your trailer brakes. To see an install video, click on the provided link.
view full answer... - Trailer Wiring Recommendation for a 2012 Honda OdysseyFor your 2012 Honda Odyssey I have a solution for you, but the part # 118438 is not confirmed as a fit as it stopped fitting the Honda Odyssey after 2010. Instead for trailer wiring you would need the part # 118521.
view full answer...
Do you have a question about this Custom Fit Vehicle Wiring?
Info for this part was:
Test Fit:
Joe V
Test Fit:
Nicholas E
Test Fit:
Andrew S
Test Fit:
Brent H
Test Fit:
Shane H
Expert Research:
Mike L
Expert Research:
Michael H
Expert Research:
Reno H
Expert Research:
Jameson C
Expert Research:
Brandon M
Expert Research:
Adam R
Video by:
Andrew K
Video by:
Zach D
Video Edited:
Joshua S
Video Edited:
Jacob T
Video Edited:
Mike H
Video Edited:
Dustin K
Video Edited:
Chris R
Updated by:
Laura H
Updated by:
Wilson B
Updated by:
Alexander C
Updated by:
Isabelle B
At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.
Product Experts Available Now!
Call 1-636-245-6296
Thank you! Your comment has been submitted successfully. You should be able to view your question/comment here within a few days.
Error submitting comment. Please try again momentarily.