Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.
CALL NOW - 800-298-8924
Product Experts Available Now!
Quickly and easily install a 4-way trailer connector on your GMC Sierra. This T-One typically plugs directly into the back of your factory-installed 7-way connector so you can retain the 7-way and also pull a trailer that has a 4-pole flat.
This custom-fit T-One connector plugs into your GMC Sierra's wiring harness, which is located behind the rear bumper. If you have a factory-installed 7-way, blade-style connector, the T-One will plug in between the 7-way and the OEM socket.
Once installation is complete, the 4-way flat connector will be stowed beneath your GMC Sierra, 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.
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.
Today, we're going to review part number 118384. This is the tow-ready T1 vehicle wiring harness with the 4 way flat trailer connector. Now, this part is designed to fit many Dodge, GM, and Nissan vehicles that have the factory tow package. I do recommend to use the fit guide on our website to help determine if it will fit your particular vehicle. This part will provide a 4 way flat trailer connector at the back of your vehicle to power your trailer's signal lights. Now, it is designed to tee into the factory-installed tow package. Now, on the factory-installed tow package, if you do have the factory-installed 7 way on the vehicle, what you can do is unplug the harness from the back of the 7 way, go ahead and plug this into the 7 way, plug the harness into this, and then that will give you the 4 way in addition to the 7 way.
In other words, it will retain the 7 way functions on the factory-installed 7 way, if you do add this into it. Now, on some factory tow package, they might leave off the 7 way at the bumper. So basically what you want to do is look under, behind the rear bumper, and you'll usually see where the factory tow package, wire, and harness will end, and then they usually have a cap on the end of it. What you want to do is take that cap off, and again, basically, plug this into the wiring harness, take that cap that you removed, and put it back in here, since you won't have the 7 way on your vehicle, and then you'll at least have the 4 way to the back of your vehicle. This is very easy to quick connects very quickly and easily. There is no cutting or splicing of the wires.
Basically, it is constructed of 16 gauge bonded wire. Now the 4 way, if you notice, does come with this dust cap that's connected. So, when you plug it in, when you're not using it, you can just put the dust cap on to protect it, keep it from corroding, or any damage to it. Now, this wire loom itself, if you stretch it out and measure it, it is about 36 inches long, and it does come with these instructions, which are very good, and they also have some good pictures to show you how to connect it. That should do it for the review on part number 118384, the tow-ready T1 vehicle wiring harness with the 4 way flat trailer connector. .
Average Customer Rating: 4.9 out of 5 stars (105 Customer Reviews)Quickly and easily install a 4-way trailer connector on your vehicle. This T-One typically plugs directly into the back of your factory-installed 7-way connector so you can retain the 7-way and also pull a trailer that has a 4-pole flat.
by: DALE N.03/26/2012
TRAILER WIRING HARNESS WENT TOGETHER REAL GOOD. IT ONLY TOOK A VERY LITTLE TIME TO INSTALL. THIS MADE INSTALLING MY LED BRAKE LIGHT KIT VERY EASY. 35167
by: Ralph S03/19/2012
Perfect fit on my 2012 Jeep Grand Cherokee. Hitch and wiring harness installed in 20 minutes. This is my fifth hitch and wiring harness purchased thru etrailer and have yet to be dissapointed. Both the video and written instructions were spot on, the installation of the wiring harness couldn't be easier! 34414
by: Damian R03/17/2014
Excellent product and easy to install! Finished up the installation with products 118144 and 118140 for a clean looking install. 121048
by: Teddy B.08/22/2011
etrailer.com had the best price around on this wiring kit, their site was easy to navigate and they upgraded my shipping from 5 to 7 days to 3 to 5 at no extra cost to me. The tracking info page was updated frequently and the map feature was a nice touch. The package came in and we were able to hook it up in a matter of 30 seconds, great fit and works perfectly with the trailer. Overall I'm very happy with my transaction with etrailer.com and would not hesitate to order from them again. 22454
by: E WHITESTONE04/23/2012
On my 2012 GMC Sierra, this was the best way to retain the 7 pole factory connection and also have a 4 pole connection. This product lets me have both 4 and 7 pole connections available at the truck, all the time, without adaptors to carry around. Most of the light trailers I pull have the 4 pole connection. I don't use the factory 7 pole very often. Installation is about 2 minutes. Check out the video on this product, it's very helpful. 38140
Received complete order and was very well packaged. It was a one man job and took me about 1 hour to install the trailer hitch receiver. Most time was consumed because of rust in screw holes. I also ordered the wrong wiring harness. I called and a replacement is on it's way along with return information to send wrong harness back for credit. Thank you very much. 79656
by: Ron H.02/14/2014
This was a very simple harness to install. Appears to be very good quality. Saves you the time of having to splice a 4 prong connector later. I coupled this with the twist in 7 prong to replace the "dummy" plug on my 2007 Sierra. The whole process took about 15 minutes. Well worth the money. The hardest part of the whole install was hiding/tying up the wires. 116589
by: Bob O06/19/2011
the trailer hitch adapter I bought for my GMC truck was just what I needed to attach an LED lightbar below the tailgate and still have a plug for a trailer. There was a short in the plug but it seems to be working ok as I just bent the wire and wiretied it in place to keep it working. The shipping was prompt and rapid and much appreciated 17257
by: Arnold C01/13/2014
I am very pleased with the T-0ne 4-pole flatTrailer Connector #118384. This is what I have been looking for months. The whole connection and wire-tie's support took me fifteen minutes. The longest time, 10 minutes, was spent supporting the extra cable to the frame with wire-ties. eTrailer is definetly on my browser favorite list! 112712
by: Tom matheny10/21/2011
your price was almost half the price at the u-haul place here in tulsa ok the phone personal really guided me thru getting the RIGHT part which has sometimes been a bad experience. thanks for the follow up e-mails that helped me track the shippment. I would and will recommend etrailer to all my friends and family 25932
by: Kennith P02/21/2012
I actually ordered one of the wrong items. It was not your fault but my inattention. Your company was easy to deal with and delivered quick. I ordered the Draw Tite Trailer Hitch. I installed it by myself and it took about 30 minutes and bolted right to the frame and all the necessary hardware was there. 32081
by: Piano Steve05/16/2013
Took me all of 30 seconds to install this product. I'm using it for an additional 4 prong plug to attach a tailgate bar from Recon. Was also able to attach the reverse, and power lines with just a quick cut and splice. Now if I remove the tailgate bar, I can remove the wires, in seconds. 80554
by: Chuck C05/06/2014
Great item. So much easier to use than cut and splice. Used it to make a quick disconnect for my Leer Camper Shell. I have a few aux. lights both exterior and interior and this makes it a breeze to run a 4 wire connector kit up to the bed for those times where the shell gets removed. 129097
by: Chris G03/26/2014
Very impressed with your company. I knew at all times the status of my order and shipping was fast and prompt. Was very easy to find the compatible product on your site as well. Would definitely shop with you again. Also loved the multiple emails giving me updates of my product. 122397
by: Clement N.05/12/2014
I'm so glad that I bought this product it really fits on my truck also it was very easy to install, now I can install my led bar light without having the wire sticking out, I hide the connector under where the spare tires is at. Thnx again etrailer! Awesome product!?? 130126
by: Dan P.05/03/2013
Great product,took less than 2 minutes to connect to my 04 Silverado stepside. Made hooking up tailgate led's a lot faster and made the installation look professional. I will be ordering from these guys again. Thanks ! 78806
by: Ray N.09/17/2012
This was the easiest harness I have ever installed. There was more than enough wire for to remove the 4 pole connector and install my 7 pole round connector. Being able to keep the 7 pole flat connector is also a bonus. 54970
by: Matt H10/16/2014
Bought Fire Lights for my 2010 Chevy Silverado hides the connector perfectly. Works well installed one on my uncles 2014 GMC Sierra for his fire lights even worked for him. Great products Great Service 156359
excellent product, just what i was looking for, easy install in just minutes (for 2008 silverado), tidy look, beats the heck out of the wires hanging from my old nissan taillight rig up in the past. 75410
The product did exactly what it was meant for. Easy to install. I used it so I could plug in an led light bar on the back of my truck so I didn't have to use my 4 port plug or do any hard wiring. 68203
by: Donn D01/07/2013
A high quality exactly as described product,that fits perfect,and was shipped very fast. My second order this month,and like the first went very smooth with GREAT follow up---Thank You e.t. 62590
by: Wendy J.01/30/2012
wow! you guys are great! super fast shipping! we have ordered from etrailer twice now and will definately order again. Great customer service and super fast shipping, couldnt ask for more! 30562
by: phil perto12/07/2012
I have 2012 Dodge Ram with towing hook up in rear bumper this adapter part#118384 fit perfect up behind bumper nice clean install. works great with my tailgate led lights thanks etrailer. 60894
by: Benjamin Harris01/24/2008
30 second install time. No kidding that this wiring harness took a simple 30 seconds to install. Plug it in and you are done! Great product and I love that no splicing is involved. 585
by: Lee D01/10/2011
Everything Great ETrailer is on top of their game. Excellent product which performs exactly as advertised, great communication, and fast shipping; they have the whole package. 5290
by: Bill in CT05/03/2013
Installed in 5 minutes, 2009 Silverado with Tow package. Now I have the 4 pin behind the bumper so I can hook up a tailgate light bar without using the 7 in outlet. 78843
by: Shayne T.05/14/2014
This is a great idea. I am going to use this to power my tailgate light bar. This saves so much time and hassle. Thank you etrailer for this great item. 130672
by: Dennis C.07/03/2013
WAS VERY IMPRESSED WITH THE T ONE WIRING HARNESS AND THE SHORT AMOUNT OF TIME IT TOOK TO SHIP.I WOULD USE E TRAILER AGAIN THANKS FOR THE GOOD SERVICE. 87520
by: Steve W.01/08/2012
Excellent product and service, fit perfect as described and took about 5-10 minute to install !!!! No cutting or splicing of wires, VERY NICE !!!! 29289
by: Josh P.05/10/2012
So easy that I showed my 7 year old how to do it, and i am not even kidding. He points out where the connector goes on every GMC he sees. 39953
by: Bill K05/12/2011
Adapter harness for my 08 Chev Silverado 1500 fit perfectly and I used it to hook up a Fire and Ice Light strip on the back of my truck. 13657
by: Tibor H.03/04/2012
It was a very easy installation process, all I have to do now is ops check it with the trailer. I would highly recommend this product. 33084
I haven't installed the product yet but it looks fairely simple to install. The shipping was fast and the product was as advertised. 46708
by: John L.12/05/2011
Great product selection. Had exactly what I was looking for. Fast service with excellent e-mail follow-up information re shipping. 27736
Item worked perfect!!!! Took less than a minute to install. Took longer to arrive than expected but still very happy with it! 112134
Plugged t-one wiring harness to existing factory harness to use my led tailgate lights. Took all of 10 minutes. Great harness! 116125
Product works as described and it very simple to install. Shipping was on time and everything was great. Will buy from again! 62379
by: Raymond Housler07/22/2011
This adapter made adding a 4 flat plug to my 2009 GMC Denali Truck a Breeze only took about 5 mintes to hook up. Great Product 19937
Exactly as described. Work Perfect! I used it for the 3rd taillight bar under my tailgate so that all the wiring is hidden. 63685
by: Eric M.05/01/2012
Just like the informercial on your website shows you, takes seconds. I also put the trailer hitch on in about 15. Easy... 38968
by: Tony J.05/17/2011
e-trailers prices were very competitive and the item was shipped quickly and an easy t install. thanks e-trailer. Tony 14544
Just plug and play, I like that. Would like see a little dab of dielectric grease on the adapter part of the plugs. BP 15123
by: Herb A.06/12/2013
This as simple as it gets to install. 15 minutes and you are completely done and ready to hook up to your trailer.. 84312
Professionally Done. Installed in less than 3 minutes. 71320
by: marcus simpson09/11/2013
The wiring harness was easy to install and the twist in connector fit good Insructions were easy to follow. 99472
by: Paul Bradbury01/04/2014
The adapter worked flawlessly and as advertised. It took all of 5 minutes to install. Great product! 111889
by: John M06/28/2013
Took me less then 5 mins to install. The video was. Great help. Product looks clean and works great. 86620
Haven't installed yet but expect it to do everything I want it to do. Looks like a quality product. 63945
by: JOHN G06/22/2012
Easy to install - does what it is suppose to do. I now have both 7 & 4 pinn connections on my truck. 45208
by: Neil C06/13/2011
Product as described and fast shipping. 2nd time using etrailer and they are 2 for 2. Thanks!! 16876
Ask the Experts about this Tow Ready Custom Fit Vehicle Wiring
Do you have a question about this Custom Fit Vehicle Wiring?
Info for this part was:
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.