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

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

Item # 118311
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Custom Fit Vehicle Wiring

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118311 - Custom Fit Tekonsha Trailer Hitch Wiring
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Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required. 1-833-496-1390 to order Tekonsha custom fit vehicle wiring part number 118311 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 (63)
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Tekonsha Custom Fit Vehicle Wiring - 118311

  • Custom Fit
  • Trailer Hitch Wiring
  • 4 Flat
  • No Converter
  • Tekonsha

Quickly and easily install a 4-way trailer connector on your vehicle with this custom wiring harness. T-One connector plugs directly into existing wiring - no cutting, splicing or tapping required.


  • Provides a 4-way flat trailer connector at the back of your vehicle to power your trailer's signal lights
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Connects quickly and easily - no cutting or splicing of wires
    • Locate connection points along frame rail
    • Plug in T-connector
  • Constructed of 16-gauge bonded wire
  • Comes with dust cap for 4-way flat connector


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


T-One Connection Location Points

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

Once installation is complete, the 4-way flat connector will be stowed beneath your vehicle, near the trailer hitch. A mounting bracket (sold separately) is recommended to keep the connector secure.

It is recommended that you use a small amount of grease on all electrical connections - the plugs on your automobile and the 4-pole connector itself - to help prevent corrosion.

118311 Tow Ready T-1 T-Connector - 4 Wire

Installation Details 118311 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 - 118311

Average Customer Rating:  4.9 out of 5 stars   (63 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.

1975 Chevrolet C/K Series Pickup

I did receive these items yesterday and found them to be just what I needed and can work with for my 1975 Chevy Silverado c30 1t pickup. I needed not just one but two as this is my father's pickup and became my inheritance. On this pickup the whole wiring harness needed work and is now in the process of being completely replaced.
I needed two of these units due to the fact that it is hooked up to a 5th. wheel trailer so it is needing one to wire up the 5th wheel harness to the side of the bed and the other for the tow hitch assembly.
Yes I am a disabled veteran in lieu of my having back and head injuries while having served as a construction mechanic in the U.S. Navy Seabee's but I'm still a mechanic. I would like to thank you for having this product but however I just wished that there was one made for going from a 4 wire to a 7 wire T-connector but with the T-connector that allows for the adaption of allowing for the 7 wires to tow to come in from the bulkhead of the pickup and for the one outlet to allow for either one to have one set of wires for the 5th wheel hook-up or one to have one set of wires that allows for both that of the bumper along with those for the 5th wheel hook-up going to the interior side of the bed and with the third part of the T-Connector to allow for just the tail lights on these older trucks.


Plug and play, work great!

1984 Chevrolet C/K Series Pickup

Doesn't hold perfect in the 4 pin connector holder bracket but it's suitable


Perfect fit and function. Have had no issues. Installation was a breeze. Would do it again without hesitation.


Very easy installation. I appreciate the fit information available prior to purchase.

1983 Chevrolet S-10 Blazer

this fit my 1983 S10 pickup and will fit 1982-84 S10. Big improvement in the truck wiring


The wire harness was super easy to install and works perfectly. The only thing you might mention in your instructions is the potential need to replace the original flasher module with a heavy duty one. The trailer signals were weak and blinked rapidly. it took me a bit to figure out the need for the new flasher but once I did everything works fine!


Fast shipping and good quality excellent service


Great product

1979 Chevy C10

Ive installed the trailer harness for my 1979 Chevy truck.

1982 GMC Jimmy

Perfect fit, excellent quality. Thanks


Everything worked great


Super easy install, but the female end of your inline adapter didn't fit as well as the original factory. I didn't have a working turn signal on my pick up after the install. I wiggled the adapter and the turn signal started working. I pushed it in as hard as I could and taped it in place. All is well for now, but you may want to tweak the fit of your adapter. I also purchased a 4 pin to 7 pin adapter. It worked great.


Had one for my 1978 pickup sold the truck and now own a 1976 pickup had to have another harness to put in. It is easy to do and takes all the headaches out of putting in a splice in harness. If I sell this truck and get another any year I will buy again from etrailer for a plug in and play harness. Thank You Frank!


I was dreading having to splice into the taillight harness until the folks at eTrailer recommended this wiring harness. Took five minutes to install and works perfectly.

1976 Chevy C10

AWESOME!!! I went to Advance Auto, Autozone, Pep Boys, O'Reilly's and Napa looking for an adapter for my 1976 Chevy C10 Full Size Pickup and flatbed trailer and was out of luck. (In NY and TN.) Ended up with a ticket for no trailer lights. (Prior to learning about bicycle stickon battery operated lights.) Saw your awesome videos on You Tube, helpful pdf files, and product images which made me confident that this was the part I needed. THANK YOU SO MUCH FOR CARRYING THIS!!! Your website and links have been truly helpful in so many ways. This was a super easy hookup and anyone non-mechanical can do it. Came fast through UPS Standard, well-packaged, worked right away. I am super pleased. We got a lot of old pickups running around in Tennessee and I'll be sure to recommend this website to anyone in need!

1982 Chevrolet Blazer

Nice product, but unfortunately does not work correctly on Military Blazers like my M1009 CUCV. The right turn and brake signals did not work due to the way the original military trailer wiring was done. I had to splice into the military trailer wiring and now this is just doing nothing. Guess i will have to take it back out at some time. It does look to be a decent product for traditional civilian Chevy products.

1983 Chevrolet C/K Series Pickup

The wiring harness was exactly what I needed. The service from was fast and reliable. I would definitely recommend them to a friend.


About time this type of wiring harness has evolved, great product.

1979 GMC C/K Series Pickup

Found the item that I needed very easily on the web site. It appears to be very well manufactured. It arrived 2 days earlier than expected. I would recommend for all your trailer needs.

1981 GMC C/K Series Pickup

This product worked EXACTLY as it should. Easily plugged into connectors and worked perfectly. I used LARGE tie straps to hold all connections together just to be sure they don't pull apart, as my truck is used for off-roading as well.


It plug right into the truck wiring, didn't have any issues getting it installed. Good product with go price.

1984 Chevrolet C/K Series Pickup

Worked great. Has a rubber housing so it seals to the truck harness well. Would buy one again. Fast shipping too.


the item arrived ahead of projected delivery date,,,, fits and works perfect on my 1976 c-10 short bed step-side truck, saves having to cut and splice in to the wiring system looking forward to getting more items ,,for this project,, thanks

Chevrolet Blazer

Plug & play. Took :02 to install and works perfect on my mid 70’s Chevy blazer.

No complaints.
Sara - 02/11/2020

Show More Reviews

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

  • Where is the Trailer Wiring Connection Point on a 1981 Chevy CK Series Pickup
    The vehicle tail light wiring harness is located along the inside of the left rear frame rail. The harness will have a connection point with connectors matching the ends of the T-connector, # 118311, that you referenced. I added a photo of this location on a newer model Chevy, the connector is different but the location is the same.
    view full answer...
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  • Factory Connection Point for Trailer Wiring on a 1984 Chevy Blazer
    As far as I could find the connection point on the 1984 Chevy Blazer is located along the driver side frame rail near the back of the vehicle (see instructions link). You may be able to pull it down from in front of the gas tank or up and over the frame rail. Otherwise, the way that you have described it, sounds like you would have to lower the gas tank to reach the factory connection point.
    view full answer...
  • 4-Way Trailer Wiring Harness Recommendation for 1984 Chevy C10
    For trailer wiring for your 1984 Chevy C10 for just the trailer lighting you'd want the part # 118311 which covers all of the trailer lighting functions.
    view full answer...
  • Availability of Trailer Wiring that Fits 1975 Chevy C10
    Yes we do have a t-harness style of trailer wiring that fits your 1975 Chevy C10 with the Tekonsha kit part # 118311.
    view full answer...
  • Does Draw-Tite Trailer Hitch Fit 1980 GMC C/K Truck
    A Sierra Grande is a C/K Series pickup, and so long as your 1980 GMC C/K truck has an 8 foot bed with a standard bumper, then yes, the following Draw-Tite hitch will fit: - Draw-Tite Max-E-Loader Trailer Hitch Receiver # 41001 Additionally, if you also need a trailer wiring harness, you can add a 4-flat connector to your truck by adding the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118311. I have added a link below to the instructions of the hitch and the harness...
    view full answer...
  • T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector 1983 Chevrolet S10
    I would agree that the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118311 looks to be a match, however this product is not guaranteed to fit your 1982-1984 Chevrolet S10 Pickup. There is a possibility that it may work but our installation and test fit experts have not verified that particular vehicle. We do carry an alternative by Tekonsha # 18252. This is a universal fit, plug and lead style hardwire kit. It also includes a circuit tester, and 4 quick splice connectors.
    view full answer...
  • Trailer Hitch Installation Instructions for a 1975 Chevy Blazer
    We have not yet had the opportunity to install the Draw-Tite hitch # 75129 on a vehicle so I do not have a picture. But I do have the instructions that shows where on the frame the hitch installs. I have included a link to the installation instructions for you. If you plan on doing some towing, I recommend the etrailer Ball Mount Kit, # 989900. It comes with 2 ball mounts, 2 balls, a hitch pin with clip, and a carrying bag. For trailer wiring use T-One Vehicle Wiring Harness, # 118311....
    view full answer...
  • Curt Trailer Hitch Receiver and Wiring Harness For a 1984 Chevrolet Short Bed C/K Pickup
    The Curt Trailer Hitch Receiver # C14082 is confirmed to fit on your 1984 Chevrolet C/K short box pickup with a step or standard bumper and frame rails that measure 34" across from outside rail to outside rail. The holes for mounting this receiver will need to be drilled into your frame. I have provided a link to the installation instructions below for you to reference. The Tekonsha T-One Vehicle Wiring Harness # 118311 will connect to your factory harness and provide you with a 4-way...
    view full answer...
  • Installing Brake Controller in 1982 Chevy K10 Blazer
    To install a brake controller on your 1982 Blazer, you will need our Brake Controller Installation Kit, part # ETBC7, which includes everything needed to install a brake controller if your Blazer has a functioning 4-pole trailer connector. If you do not already have a 4-pole trailer connector in place, one can easily be installed using a Tow Ready T- One Connector, part # 118311. I do not have any vehicle-specific installation instructions for your particular vehicle, but I have linked...
    view full answer...
    Image 1 for
  • What Trailer Hitch Will Fit My 1977 Chevrolet Pickup
    We do have a trailer hitch that will work with your 1977 Chevrolet Pickup although I doubt the one off the 1985 Suburban will work. We do not carry any hitches for the Suburban that are also compatible with the pickup. Which is a very good indication that the hitch will not be a match. An option for your pickup is the Draw-Tite Max-E-Loader Class III # 41504. It is made to fit with the heavy duty suspension of your truck. Additionally, you may be interested in the Ball Mount # EBMK4....
    view full answer...
  • Trailer Hitch and Wiring for a 1977 Chevy Blazer 2-Wheel Drive
    Curt trailer hitch # C13401 will fit your 1977 Chevy Blazer. I also checked the installation instructions, linked for reference, and it does not exclude 2-wheel drive or 4-wheel drive models so you are good to go! If you plan on doing some towing I recommend etrailer ball mount kit # 989900. It comes with 2 ball mounts; one with a 3/4 inch rise or 2 inch drop and one with a 2-3/4 inch rise or 4 inch drop. It also includes a 1-7/8 inch ball, 2 inch ball, hitch pin with clip, and a storage...
    view full answer...
  • Trailer Wiring and Brake Controller for a 1983 Chevy C10
    First, you will need a 4-way connection. The purpose of this connection is to operate your stop, turns, and tail lights of your trailer. The T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118311 will quickly and easily allow an install of a 4-way trailer connector on your Chevrolet C/K Series Pickup with this custom wiring harness. T-One connector plugs directly into existing wiring no cutting, splicing or tapping required. In order to control your trailer with electric...
    view full answer...
  • Recommended Trailer Brake Controller for Use in 1984 Chevrolet K20 Pickup
    To install a trailer brake controller in your 1984 Chevrolet K20 Pickup you will need the brake controller itself, such as the excellent Tekonsha Primus IQ # TK90160 that you referenced, as well as a brake controller installation kit # ETBC7. If your truck does not already have a working 4-pole flat trailer connector you will also need one those, part # 118311. Your installation will be a hard-wire type since there is no quick-connect port under the dash. At right you will find links to...
    view full answer...
  • Trailer Hitch Recommendation for a 1978 Chevy K20 * Foot Bed with Standard Bumper
    Draw-Tite trailer hitch # 41938 will fit your 1978 Chevy K20 if it has the standard factory bumper and it the distance from the end of the frame to the leaf spring shackle bracket is 19 inches or more so since yours are at 14 and 18-1/2 this hitch will not fit. You can instead use Ultra Frame Trailer Hitch Receiver - Custom Fit - Class V - 2" Item # 41947. I have linked the installation instructions for you. I also recommend Ball Mount Kit - 3" Rise or 4" Drop - 16,000 lbs...
    view full answer...
  • Will the Draw-Tite Hitch # 75034 Work on a 1978 Chevy C-10
    The only modifications you will need to make on your 1978 Chevy C-10 2WD to install this Draw-Tite Max-Frame Trailer Hitch # 75034 will be that you will need to drill a few holes and relocate the spare tire mount. I attached installation instructions for you to check out for this product. You may also be interested in purchasing the following products to complete your tow setup: T-One Vehicle Wiring Harness with 4 Pole Trailer Connector # 118311 (instructions attached) Ball Mount # 2753 Hitch...
    view full answer...
  • Brake Controller Installation on 1979 GMC Jimmy
    A brake controller like the Tekonsha PowerTrac # 39523 you mentioned is not a vehicle specific item. A brake controller can be installed in just about any vehicle. You would need a brake controller installation kit, part # ETBC7 if you needed a 7-way trailer connector or # ETBC6 for a 6-way connector. The install kits include everything necessary to install a brake controller, including the 7 or 6-way trailer connector that is designed to adapt an existing 4-pole trailer connector. If...
    view full answer...
  • Trailer Hitch and Wiring Harness Recommendation for 1978 Chevrolet K20 Pickup with Step Bumper
    For your 1978 Chevrolet K Series with step bumper, I recommend the B&W Heavy Duty Trailer Hitch Receiver # BWHDRH25198. This trailer hitch is designed to fit the 1978 C/K Series Pickup with an 8 foot bed with a deep drop bumper. This trailer hitch will meet the weight capacity needs you referenced, offering 1,600 pounds tongue weight and 16,000 pound towing capacities. This hitch has a powder coat finish to help resist rust and has safety chain loops built in. I have attached a photo...
    view full answer...
  • Recommended Trailer Hitch For 1978 Chevrolet C10 Pickup Truck
    We do have trailer hitches that do not require drilling for installation, but they are only designed for a 1978 truck with a deep drop bumper. If you have a deep drop bumper I recommend part # C15511. This is a Class V hitch and it has a 2-inch receiver opening. If you have a standard bumper on your truck, the trailer hitch I recommend is part # C14082. Installation of this hitch does require three holes to be drilled into the frame for each side. If you plan on doing some towing you...
    view full answer...
  • Parts Needed to Install a Trailer Brake Controller on a 1978 Chevy C/K Series Scottsdale
    First, you will need to install a 4-Way trailer connector, # 118311. I have included a link to the instructions for you. Next, you will need a 4 and 7 way installation kit, # ETBC7. This will provide the 7-Way and the wiring to install the brake controller. I have included some links that will help with the ETBC7 installation. You will also need a second cradle and mounting bracket for the second vehicle, # TK5906. And you will need another wiring harness for the second vehicle. Depending...
    view full answer...
  • Hitch Recommendation for 1974 Chevy C10 Stepside Pickup
    If your truck has the standard bumper, I'd recommend the Draw-Tite Class III hitch, part # 75034. If you have the deep drop bumper, use the Draw-Tite # 41504. I've linked you to an FAQ article that explains the difference between the standard and deep drop bumper. If you need to install a 4 pole trailer connector, use # 118311. You might also need a ball mount like # 2753, a 1-7/8 inch trailer ball like #19260 or a 2 inch trailer ball like part # 63845.
    view full answer...
  • Class V Trailer Hitch Recommendation For 1973 Chevrolet C/K Pickup
    The B&W Heavy-Duty Trailer Hitch Receiver, part # BWHDRH25122, is verified to be a fit if your 1973 Chevrolet C/K Pickup has an 8 foot bed and a standard bumper. This hitch is a Class V hitch and has a 2 inch receiver opening. We have not received any feedback from customers about the hitch not fitting. For a ball mount I recommend part # BWBMHD30010. This mount features a 1 inch rise and 2 inch drop and measures 8-1/2 inches from the center of the hitch pin hole to the center of the ball...
    view full answer...
  • Recommended Brake Controller And 7-Way Wiring For 1984 And 1985 Chevy C10 Trucks
    For both your 1984 and 1985 Chevy C10 trucks, I recommend the Tekonsha Prodigy P3 Trailer Brake Controller - 1 to 4 Axles - Proportional # 90195. If you will not be using the vehicles at the same time, you can use one controller and just add the second harness # 20127 and bracket # 2178. You can then use the Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires # ETBC7 on each vehicle to get your 7-way connection and wiring. This kit will...
    view full answer...
    Image 1 for
  • Trailer Hitch and Wiring for a 1977 Chevy C10 Pick-up with 6 Foot Step Side Bed
    We do have trailer hitches that will fit your 1977 Chevy C10 short bed but # C13099 is only for long bed models. For your truck you can use Curt trailer hitch # 13028 unless it has the 10 inch deep drop bumper. If it does have the deep drop bumper you can use # C15511. If you plan on doing some towing I recommend etrailer ball mount kit # EBMK4. It comes with a ball mount with a 2-3/4 inch rise or 4 inch drop, interchangeable ball set, hitch pin with clip, and a storage bag. If the ball...
    view full answer...
  • Will Spare Tire Interfere with Trailer Hitch Installation on a 1978 GMC C/K Series Pickup Truck
    The Curt trailer hitch # C14082 is designed to attach to the bottom of a 34 inch wide frame on a cab and chassis model 1978 Chevy C/K series pickup. If the spare tire fits between the frame rails then it will not be a problem, otherwise it would need to be relocated or the mount modified. If you do not have a cab and chassis model truck this hitch will not fit. I have linked the instructions for you to view. I have also linked the other hitches for your truck in case you do not have a...
    view full answer...

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