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

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

Item # 118685

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Our Price: $120.45

Custom Fit Vehicle Wiring

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Tekonsha Trailer Hitch Wiring - 118685
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Product Images

In Use/Installed

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  • Custom Fit
  • Trailer Hitch Wiring
  • Tekonsha
  • 4 Flat
  • Powered Converter
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. Call 800-298-8924 to order Tekonsha custom fit vehicle wiring part number 118685 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.


  • All Info
  • Reviews (88)
  • Q & A (37)
  • Videos (3)
  • Photos
  • Why etrailer?

Tekonsha Custom Fit Vehicle Wiring - 118685

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.


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
    • Locate connection points behind tail lights
    • Plug in T-connector
    • Connect hot lead to battery
  • Includes ModuLite power converter to ensure that your vehicle's wiring matches that of your trailer
    • Powered module connects 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: 5 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 and passenger's-side tail lights. You will have to remove the tail light assemblies to access this harness.


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 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.


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.



118685 Tekonsha T-1 T-Connector - 4 Wire - Modu-Lite Converter Included



118685 Installation InstructionsInstallation Details 118685 Installation instructions

This Product Fits The Following Vehicles

2016 - 2019 Toyota Tacoma

2016 - 2019 Toyota Tacoma



California residents: click here


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


Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.




Video Transcript for Trailer Wiring Harness Installation - 2017 Toyota Tacoma

Speaker 1: Today on our 2017 Toyota Tacoma, we're going to be installing the T1 vehicle wiring harness, part number 118685. This wiring harness is going to provide you with the connector and all the necessary signals you need for your trailer.It's going to provide your taillights, your turn signals, and your brake lamps. Everything you need to install it comes included in the kit. It's got a control box, which is going to isolate the factory circuitry on your vehicle from the harness in your trailer. So this will protect your vehicle from any over current or shorts that's on your trailer. It's easy to install.

Let's show you how to do that now.We'll begin our installation by removing the taillights. You'll need a 10 millimeter socket. You'll remove the one bolt at the top and the two bolts at the bottom. Once the bolts are removed, you'll want to pull towards the rear to release the alignment tabs. There's one on the top and one on the bottom.

Next you'll want to remove your top lamp connector. Push in on the tab and pull outward to release it. We'll take our harness and we're going to plug the female end into our light. Then we're going to plug our male end into the connector that we just disconnected.Next we're going to clean an area, so we can mount our control box. Want to use some alcohol or soapy water to clean all the dirt and debris away from where you're going to stick the adhesive.

Next we'll put our adhesive pad on the back of our control box. Peel away the protective cover. We can mount right in this pocket back here. Want to hold it for about 25, 30 seconds to make sure that it sticks.Once the adhesive is stuck, feed your wiring down through the open pocket. Next we're going to install our ground wire.

The kit comes with a self tapping screw. We'll use this screw just to mount it right here inside of our pocket. We can tuck the excess wire back. Now we're going to take some of the black wire that comes in our kit. We're going to strip back a little bit, so we can attach it to our power wire on our control box. We'll go ahead and take our heat shrink butt connector and crimp it onto our power wire on our control box.We'll then take our black wire in our kit that we stripped back. We'll take some of it loose from the rubber band there. And it'll be easier if you feed up underneath following the wires we fed through earlier and feed it back up through the hole. Now we can crimp it onto the same connector that we crimped our power wire to on our control box. Now we'll use a heat gun to shrink down our butt connector. This'll keep out any moisture and contamination to keep those corrosion free.Now we're going to route our red wire over to our passenger side. We're going to run these wires over to the passenger side. Trying to avoid any heat sources such as exhaust pipes. Then we'll go up through our passenger taillight hole. Then we'll run our four way connector over. And we can tuck this up then we'll choose the appropriate length that we want sticking out at the bottom here. Now on our passenger side tail lamp, we can disconnect the same connector we disconnected on the driver's side. And we're also going to disconnect our middle bulbs connector.We're going to plug our harness into those using the female sockets. And then plug our factory vehicle harness into our male sockets of our trailer harness. With everything connected at the back of out taillight, go ahead and reinstall it. Clicking your tabs into place, reinserting your bolts. You'll tighten them down with your 10 millimeter socket and repeat this same process on the driver's side.Next we'll take a line such as this air tubing here and run it down, so we have something to attach our wire to, to pull it back up. We're running it on our driver's side because this is where our battery is. We can connect to that. When you run this down, you want to avoid any moving or hot objects such as exhaust or suspension components. With the rest of our wiring ran, all that's left is to run our power wire to the front where it'll be connected to your battery. I'm going to run that now and I'll show you how I routed it. Remember when routing your wire, you want to avoid any hot objects such as your exhaust and moving components such as steering and suspension.If possible, follow you factory wiring. Now we routed our power wire, just following right along our factory wiring harness. Up over our tank, right along the side following the factory harness, crossing over the frame rail where the factory harness does. Running it right along the harness on the outside and again crossing back in where our factory harness does. Here we've got our air line tubing that we ran down earlier. Use some electrical tape to go ahead and connect it there. So we can pull it back up on the top side.Now we'll pull our wire up. It's a good idea to get back underneath and check and make sure no wire got hung up on anything. In your kit you'll have a fuse holder with a looped wire. Fold the wire in half and cut it in the center. Now strip back both ends of this wire. You'll attach the yellow eyelet to one end. And the other heat shrink butt connector the other. Using a 12 millimeter socket, loosen the small battery positive wire there on top of your battery post. Slide on your yellow eyelet and tighten it back down.Now we're just tidying up our black wire we ran before and running it up to connect to our fuse we just installed. Again we're just following the factory harness whenever possible. This gives it a clean look and you know it'll be in a safe location because your factory harness won't be routed in a way that it would be in harms way. If you have a little bit of excess, that's okay we can zip tie up that excess. This way in case you need to change anything later, you'll have some leeway. You also have the option to cut it and then connect it. But we're going to leave this little extra.Once you've got your black wire run, go ahead and crimp it onto your fuse butt connector and then heat shrink that connector down. Now we can install our 15 amp fuse and test everything out. Now we can make sure everything's working properly. You can use a light tester such as this one here. Which can be found at etrailer.com, part number I26. We're going to run through all of our lights. We have our taillights, left turn, right turn, and brake lamp. With everything working properly, we're ready to hook up our trailer and hit the road. And that completes our installation of the T1 vehicle wiring harness on our 2017 Toyota Tacoma.


Customer Reviews

T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector - 118685

Average Customer Rating:  4.8 out of 5 stars   (88 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.

- 118685
by:

This wiring harness was easy to install. I have made up my own harnesses for years , thank goodness for the improvements. The instructions were good. Ups sent my wiring harness and hitch to he wrong address as usual. 619628



- 118685
by:
Jeep

would not buy from anyone else these guys are great just try to go to a trailer hitch shop and see how you get treated then try etrailer and see the difference you order you receive very fast and you install your self or simply ask a good mechanic shop to install it if you are not familiar with wires etc and in addition etrailer will guide you thru the process over the phone or online never had a problem out of my many jeep projects nor trucks and I am only a house painter who hates assembling stuff my current hitch and huge wire assembly was installed by a tire co in 30 minutes like factory for $100 hitch shop wanted $375 and they would`nt do it unless they welded it h*ll no on a $ 60.000 truck it bolts on perfectly tx again george 332794



- 118685
by:
2016 Toyota Tacoma

I ordered this along with a Draw-Tite receiver hitch for a 2016 Tacoma SR 2.5L so that I could occasionally pull a small utility trailer. No factory trailer attachment options were available from the factory so this was the next best thing. Etrailer had videos out regarding the hitches and the trailer wiring options for the Tacoma before I ordered the vehicle which was very helpful. After I had the vehicle for a year or so I finally ordered the hitch and trailer wiring. The products shipped quickly and arrived promptly. The installation instructions were clear. You will need to run a 12v hot lead to your battery so it will take some time to install but it's pretty simple. The kit includes some wire ties but you will need more to do a tidy job. I also purchased some plastic wiring loom/conduit locally for better protection. I mounted the control module in a different location than what the etrailer video shows. I was able to mount it in the driver side taillight well directly behind the light assembly. It was tight but I thought the location offered better protection. After installation I decided that I didn't like the trailer wiring plug hanging under the vehicle so I found the Hopkins 41144 vehicle wiring kit fit in the bumper like from the factory. I simply bought a spare 4 prong trailer plug and with some crimp on connectors attached it to the Hopkins 4114. Now the truck looks factory and the trailer wiring is better protected. 512316



- 118685
by:
2017 Toyota Tacoma

everything came correctly , no missing parts. installed and working perfect. only flaw is the adhesive contact, it's does not look is gonna hold control box for so long. I hope it would. thankyou guys... 496877



- 118685
by:
2019 Toyota Tacoma

Pleasantly surprised at how easy it was to install both the hitch and wiring harness, thanks to the videos. The only down side was not having a lift. 663440



- 118685
by:
2019 Toyota Tacoma

Having the wire harness was a definite must in making the installation of the trailer light hook up. It was as easy as the video said. Unplug and plug in. The most difficult part of the process was running the power wire to the battery. Over all I’m satisfied to the highest level with this product. 662447



- 118685
by:

easy installation, works great. 662422



- 118685
by:

Product arrived today. I have not installed it yet but looks like fine quality connectors and wiring. Looks easy to install. 658177



- 118685
by:
2019 Toyota Tacoma

excellent product for my Toyota Tacoma 2019 ... quality and expected delivery... 655754



- 118685
by:
2019 Toyota Tacoma

Very easy installation. 2019 Toyota Tac oma. 654349



- 118685
by:
2019 Toyota Tacoma

Wiring harness was perfect fit. It was an extremely easy install. 652079



- 118685
by:
Toyota Tacoma

I signed up with you for snail mail, the least expensive (ground delivery) of my package and it turned out to be a huge mistake. As it turned out, I obtained the services of an experienced mechanic much earlier than I thought, and we just had to wait around while, by the UPS map, my package was sent north from Missouri to Lake Michigan, etc., etc., and sat in my city of Gaithersburg 3 days before they delivered it??? I would have gone to get it if I could have found out where it was in Gaithersburg. Never again UPS. My mechanic needed almost 3 hours install the of wiring and connections kit (Tekonsha 18685), so I don't think installation was simple, easy, quick and something that an amateur could do. The box comments were written by a raving optimist. But when installed, the kit worked correctly to connect my Tacoma lights to my trailer. Yippee!!! Greg, your salesperson was a pleasure to deal with, but tell him I said to talk people out of snail mail. 651749



- 118685
by:

It fits in like a puzzle. Easy to install It has all the parts you need. Thanks for the follow up 651619



- 118685
by:

Hitch, wiring harness and receiver shipped quickly and received product exactly as described. Installation of harness was made very quick and easy by following your video. I've already recommended etrailer.com to others and will continue to do so. thank you!! 649457



- 118685
by:
2018 Toyota Tacoma

Great product. The written directions were a little more difficult to follow than watching the video. With video guidance the install went perfectly with no hiccups at all. Everything worked perfectly when connected to the boat trailer. Highly recommend for a 2018 Tacoma. 646851



- 118685
by:

I was very pleased with my hitch recievers and wiring package they both fit perfectly and both were easy to install 644862



- 118685
by:
2019 Toyota Tacoma

Installed in less than 30 mins. Super easy to install 642986



- 118685
by:

I like the products that I get from you in the quality and how they hold up 640143



- 118685
by:
2016 Toyota Tacoma

Great videos explaining the installation. Works just perfect. 637586



- 118685
by:
2017 Toyota Tacoma

Product was very easy to install. Fast shipping also 633666



- 118685
by:
2017 Toyota Tacoma

The product itself appears to be good quality and fit exactly as it should. The problem is the directions supplied with the wiring kit, which were very poor. However, watching etrailer's excellent installation video made installation simple. 633572



- 118685
by:
2017 Toyota Tacoma

Simple plug and play installation, especially if you watch the install video. Everything worked like a champ on the first go. No issues at all. 619281



- 118685
by:

Finding what I needed could not be more simple. Ordering Simple and Easy. How-To videos are a HUGE help and spot on! VERY Satisfied Customer! 613246



- 118685
by:

This was very easy to install, took about 45 minutes over all. Instructions were pretty good, were easy to follow. Yes I would recommend this product. Works great! 613084



- 118685
by:
2016 Toyota Tacoma

Great Company Great Products Great Reviews Have nothing bad to say Company delivered a great product and it was easily installed 611825



- 118685
by:

It fitted like a glove 607101



- 118685
by:
2019 Toyota Tacoma

Great online installation video. Easy to install. Running power wire to the battery is a pain, but necessary. Powered up without issue. 603841



- 118685
by:
2018 Toyota Tacoma

Tried 5 different auto shops and none carry this wire harness. The auto shop want to charge me $290.00 to make me one. Went to the online and entered wire harness for my toyota and found the video. Look the video and order your part. It took me 35 minutes to installed it on my truck. Just like the video explain. Give it a go. Nothing better. Only one minor complain and maybe can be done by manufacture. The cable thet goes to the battery is black. Thiis csble goes to the positive post. Please change the color. If vehicle goes to a Auto shop for repairs. The black cable is always negative. But on your case is positive. 601180



- 118685
by:

Excellent customer service and support. I will certainly buy from etrailer.com again. 600022



- 118685
by:
2017 Toyota Tacoma

Hooked up nicely. Makes it super easy to install versus paying a couple hundred dollars to have someone install one. 599262



- 118685
by:
2018 Toyota Tacoma

Was supposed to have 25ft of black power wire but only came with 10. Unable to make connection to battery. Rest of the harness was fine. They are sending me the rest of the wire but quite an inconvenience. 588834



- 118685
by:
2018 Toyota Tacoma

Got my items on time, just as described 584511



- 118685
by:
2018 Toyota Tacoma

The 12V cable is adequate length but the wires between both taillights are not long enough if harness is routed along factory harness path! I mounted the controller module inside the left taillight housing and routed the wires to the right taillight housing. Fortunately I can solder well and am an avid electronics hobbyist so I was able to add about 8 in. of wire. Not sure if was a mistake or by design. The cynical side of me says it's the latter not the former... The only way to get it to fit without modification is to mount the control module at the very bottom of the taillight housing then stretch the wires across to the passenger side, not following the path of the original factory harness. Product works well though; concerned about durability though. 584475



- 118685
by:

Great product fast shipping easy install 584215



- 118685
by:

Great product thanks 584180



- 118685
by:
2018 Toyota Tacoma

Wiring kit was very very easy, do not be afraid to do it your self. If you can change a light bulb you can do this. 582359



- 118685
by:
2017 Toyota Tacoma

Excellent kit. My only complaint is I think the wires going to the passenger side could have been 3-4 inches longer. Kit also had a nut but I didn't see where it was to be used. Excellent video. 580105



- 118685
by:

This product paired with the installation video made it super easy to install. I knocked it out in about an hour with no special tools. Might be nice to include two self tapping screws so the box can be secured and the ground wire attatched without having to hunt down one extra self tapping screw to complete the project. 579811



- 118685
by:
2018 Toyota Tacoma

As always the products at e-trailer are great, they fit perfectly and customer service is excellent. The trailer wiring harness for the 2018 Toyota Tacoma fit like factory, I was very pleased. Thanks. 578104



- 118685
by:

Fast shipping easy to install 571592



- 118685
by:
2018 Toyota Tacoma

Installed easily & works great. The video was very helpful. 568228



- 118685
by:
2018 Toyota Tacoma

I could not believe how easy this was to install. We did refer to the online video for confirmation of what we were doing. But the step by step instructions were right on target. Shipping was fast. The description matched perfectly. Took us about an hour to do because we kept taking breaks and having fun. It could easily been installed in 30 minutes. We have a 2018 Toyota Tacoma. 566600



- 118685
by:
2018 Toyota Tacoma

Easy way of avoiding dealer's pricy harness.took less than a hour and when done,i was extremely happy.added 4 to 5 pole adapter for my trailer disk's brakes. 558353



- 118685
by:
2017 Toyota Tacoma

Product delivered ahead of time, great quality, easy to install. I will buy from this seller again. 554759



- 118685
by:

Good product, fast shipping, good communication and tracking info. I couldn’t ask for a smoother transaction! Thank you. I will be ordering more items in the future for my new Tacoma! 554421



- 118685
by:
2018 Toyota Tacoma

This is a fantastic harness, a breeze to install. Plug and play, no cutting wires. Super satisfied, shipping arrived a day early. These guys are pros, will definitely shop here again. Thanks everyone at etrailer, Well done!!! P.S. used the instructional video for the installation of this product on my 2018 Tacoma. 552738



- 118685
by:
2018 Toyota Tacoma

Trailer hitch and trailer lights wiring was delivered only four days after order was completed which was a big suprise and delivery was free. All parts fit without any problems. 549747



- 118685
by:

Fast shipment and good product 541724



- 118685
by:
2016 Toyota Tacoma

I just installed the 118685 Tekonsha wiring harness on my 2016 Tacoma. Everything fit well and the "plug-and-play" connectors matched the factory connectors on my Tacoma tail light assemblies. All wiring was the right length for the application and everything needed was in the kit. I would definitely buy this 118685 wiring harness again. 539354



- 118685
by:
2018 Toyota Tacoma

Works great easy assembly 527255


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  • No Ground Stud Behind Tail Light to Install Trailer Wiring Harness on a 2017 Toyota Tacoma
  • Since your 2017 Toyota Tacoma does not have the ground stud in question behind the driver's side tail light you would follow the alternate step in the instructions for wiring harness # 118685. And that is "Locate a suitable grounding point near the adapter such as the vehicle frame or crossmember. (Do not drill into vehicle floor or bed.) Clean dirt and rustproofing from area. Drill a 3/32” hole and secure white wire using eyelet and screw provided." Apparently some Tacomas have the stud...
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  • Recommended Trailer Hitch Receiver For 2017 Toyota Tacoma
  • For your 2017 Toyota Tacoma, I recommend the Draw-Tite Max-Frame Trailer Hitch Receiver - Custom Fit - Class III - 2" # 75238. This hitch will come with the pull wire needed and all the hardware. This is a very strong hitch receiver with an e-coat base and powder coat finish. This is a confirmed fit for your truck and I've attached the installation details for you. For your wiring, I recommend the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118685. This custom-fit...
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  • Trailer Hitch Recommendation for 2017 Toyota Tacoma
  • For a trailer hitch confirmed as a fit for your 2017 Toyota Tacoma you'd want to start with the Draw Tite Hitch part # 75238 which would fit and work well. It has more than enough capacity for a 2,920 lb pop camper like what you have. If you don't have trailer wiring you'll then need the T-One kit part # 118685 which is also a confirmed fit. I attached install videos for both of these for you to check out as well. If you wanted to do some towing you might be interested in etrailer ball...
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  • Recommended Trailer Hitch Receiver, Brake Controller, And Wiring For 2016 Toyota Tacoma
  • I'm happy to help you get what you need to tow with your 2016 Toyota Tacoma. As you mentioned, we need to start with the trailer hitch. For your application, I recommend the Draw-Tite, Max-Frame Trailer Hitch Receiver Class III, # 75238. This receiver has an easy bolt on installation that doesn't require any drilling. This will be an extremely sturdy hitch with a 2 inch x 2 inch receiver opening. Next, we will need a ball mount. I recommend the Curt Channel Style Adjustable Ball...
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  • Parts Needed to Install 7-Way on 2017 Toyota Tacoma
  • We have what you need to install a 7-way on your 2017 Toyota Tacoma. You will need to start with a 4-way (if you do not have one). For that you would want the # 118685. 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 instead of the # 37185 and a brake controller. This kit comes with everything needed to wire up the 7-way and install a brake controller. For...
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  • Adding a Second 4-Way Flat Connector to Activate Brake Lighting on a Truck Cap
  • I do have a solution for you, but we do not have any adapters that will plug into the Tekonsha T-One # 118252 and provide 2 female 4-Way flat connectors. Instead, I recommend installing the 4-Pole Hardwire Kit with Circuit Tester # 18252 and splice it into the T-One # 118245 right behind the female 4-Way. This kit comes with 6 feet of wire so if that is too much you will want to cut it before splicing the wiring together color for color. Please note that part # 118252 that you referenced...
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  • Trailer Wiring for 2018 Toyota Tacoma
  • Good choice on the Draw-Tite hitch, part # 75238. I've linked an install video from when we put it on a 2017 Tacoma. The install is the same as your 2018. I recommend the Tekonsha wiring harness, part # 118685. It has a higher amp capacity than the Curt and they both install behind the truck's tail lights. Then you run a wire to the Tacoma's battery battery to power the converter and insert the included fuse. I've linked this install video as well on the same truck for you. If...
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  • Is Trailer Wiring # 118685 for 2017 Toyota Tacoma Short Proof
  • The converter of the part # 118685 that you referenced is designed to prevent trailer wiring shorts from making it to the vehicle's wiring. What will happen is the converter box will short itself out as a way prevent the short from making it to the vehicle wiring. Bad part is that it permanently damages the converter and requires it to be replaced, but at least your vehicle will be protected.
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  • Trailer Connector for 2018 Toyota Tacoma
  • If by "brakes" you mean the brake lights then yes, part # 118685 is all you need to hook up a trailer to your 2018 Toyota Tacoma. I've linked an install video on a 2017 Tacoma for you. It plugs in to the truck's wirin behind both tail lights and then has a power wire to run to the truck battery. I've also linked an article about routing that power wire you might find helpful. If you actually mean that the trailer has electric brakes then you need a 7-way connector, part # 22117. ...
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  • Trailer Hitch Receiver and Other Parts to Tow a Trailer with a 2016 Toyota Tacoma
  • The best trailer hitch that fits your 2016 Toyota Tacoma is the Draw-Tite # 75238. It's a Class III, 2 inch hitch that bolts right onto the truck's frame. All of the necessary hardware is included. If you're going to be towing with your truck you'll need wiring as well. The Tekonsha # 118685 wiring harness provides you with a 4-way trailer connector. It plugs into the truck's wiring behind both rear tail lights and then has a single wire ran to the battery. You can mount the connector...
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  • Are the Trailer Wiring Harnesses the Same for Both a 2017 and 2018 Toyota Tacoma
  • If you are referring to a trailer wiring harness then no, the trailer wiring harness for a 2017 and 2018 Toyota Tacoma will be the same. For this, I recommend using the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector part # 118685. This harness is a direct plug and play option that will give you a 4-way trailer connector at the rear of the vehicle without requiring you to cut or splice any wires. I have attached an install video this harness on a similar 2016 Toyota Tacoma...
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  • Troubleshooting Wiring Harness Connections on 2018 Toyota Tacoma
  • The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118685 is the confirmed fit for a 2018 Toyota Tacoma. The adapter on a US vehicle will give you an adapter that will reach each side correctly. There should be a connection on each side of the vehicle as shown in the attached video. You will need to make sure the connections are made on the correct side as they cannot be reversed for proper connection and function. If you do not have a US model, then you will...
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  • Recommended Time-Delay Brake Controller for 2016 Toyota Tacoma
  • For cases where mounting space for a brake controller is limited, the time-delay type is often preferred. Unlike accelerometer-based proportional controllers like the popular P2 # 90885, time-delay units offer more mounting flexibility since they do not have to be as carefully oriented. I suggest the Tekonsha PowerTrac Electronic Brake Controller # 39523 along with plug-in wiring adapter # 3031-P if your Tacoma has the factory 7-way trailer socket at the rear bumper. If it does not...
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  • Troubleshooting Trailer Wiring Where Brake Lights Do Not Work
  • First thing you should do at this point is test the 4-way of the wiring harness with a circuit tester part # PTW2993 for voltage on all of the right pins when the taillight signals are being applied. Just like in the video I attached. If the voltage checks out there but the trailer lights still don't function right then the problem is on the trailer wiring. That would mean that problem is either due to a ground issue or a short issue. Make sure that the trailer side connector are...
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  • Parts Needed to Add 4-Way and 7-way for Brake Controller on 2016 Toyota Tacoma
  • You will need to start with a 4-way (if you do not have one). For that you would want the # 118685. I attached an install video for that for you to check out. 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...
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Info for this part was:

Edited by:
Lindsey S
Expert Research:
Michael H
Installed by:
Jeff D
Expert Research:
Jameson C
Video Edited:
Joshua S
Video Edited:
Jacob T
Video by:
Chris R
Written by:
Alexander C
Photos by:
Stacy F
Test Fit:
David F

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