1. Wiring
  2. Hopkins
  3. Trailer Connectors
  4. Trailer End Connector
  5. 4 Flat
  6. Plug and Lead
Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long

Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long

Item # HM38168
lowest price pledge
Our Price: $6.69
Orders above $50 qualify for Free Shipping
Shipping Weight: 0.27 lbs
In Stock
Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long Plug and Lead HM38168
zoom in icon
slider vertical icon
zoom out icon
Comment field cannot be left empty.
Name field cannot be left empty.

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.

Product Images


Wire your trailer with this universal, splice-in wiring harness so that you can connect the trailer's wiring to your vehicle's during towing. Corrosion-resistant terminals are long-lasting. Lowest Prices for the best wiring from Hopkins. Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long part number HM38168 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
  • All Info
  • Reviews (17)
  • Q & A (8)
  • Videos (1)
  • Photos
  • Why etrailer?

Hopkins Wiring - HM38168

  • Trailer Connectors
  • Trailer End Connector
  • 4 Flat
  • Plug and Lead
  • Hopkins
  • 6 - 10 Feet Long

Wire your trailer with this universal, splice-in wiring harness so that you can connect the trailer's wiring to your vehicle's during towing. Corrosion-resistant terminals are long-lasting.


  • 4-Way flat trailer-end connector plugs into the 4-way flat on your vehicle
    • Compatible with 5-pole, 6-pole and 7-pole adapters (sold separately)
  • Simple installation
    • Hardwire to existing trailer wiring
  • Corrosion-resistant terminals are long-lasting


  • Harness length: 6'
  • Wiring configuration:
    • White: ground wire
    • Yellow: left turn/brake light
    • Green: right turn/brake light
    • Brown: tail lights
  • 90-Day limited warranty

38168 Hopkins 4-Way Flat Connector - Trailer End - 72"

California residents: click here

Video of Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long

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

Video Transcript for Hopkins Wiring - Trailer Connectors - HM38168 Review

Today we're going to be taking a look at the Hopkins 4-Pole Flat Wiring Extension. This wiring harness is going to simply act as an extension of your trailer's wiring. It's going to feature one trailer end connector, and then this side right here is going to wire into the trailer wiring on your trailer. On the connector plug right here, we're going to have corrosion resistant terminals. These are very long-lasting. Nice, strong durable design.

It's going to have some grips here on the connector head, gives it an easy grip design. The overall harness length is going to measure about 6 feet long, so that's 72 inches. When it comes to the wiring configuration, your green wire is going to be right turning brake. Yellow is going to be left turn and brake. Brown is going to be for your tail lights, and white is going to be for your ground wire.

That's going to do it for today's look at the 4-Pole Flat Wiring Extension.

Customer Reviews

Hopkins Wiring Harness with 4-Pole Flat Trailer Connector - Trailer End - 6' Long - HM38168

Average Customer Rating:  4.9 out of 5 stars   (17 Customer Reviews)

Wire your trailer with this universal, splice-in wiring harness so that you can connect the trailer's wiring to your vehicle's during towing. Corrosion-resistant terminals are long-lasting.

- HM38168

Fast and friendly service. Package arrived on time as promised. Great company! 911685

- HM38168

Works good fits plug snug. 716026

- HM38168

Thank you for the product and prompt delivery..has been a pleasure doing business with you...G. In Ga. 604317

- HM38168

Fine 594073

- HM38168

Great place to do business with always good products and quick shipping. 565119

- HM38168

Name brand products perform as expected. 523821

- HM38168

Easy to navigate website. Easy purchase and fast shipping. 478577

- HM38168

Worked as expected. 6' was a little short for my purposes and I had to add a foot of wire. 466386

- HM38168

etrailer had the part i need which I could find no where else. Service was fast and customer service was great evidenced by an email checking that I received their product, offering installation help, and thanking me for being a customer. Pretty amazing for an online company. 432498

- HM38168

Great people to work with. Excellent prices on all trailer parts. Thanks 429136

- HM38168

This was the only place where I could find this trailer-side Hopkins flat 4-connector with 6' wire. It was exactly what I needed, but I couldn't find anywhere else. I've installed it as part of a total trailer rewire and it works fine. I wanted Hopkins because they use a much heavier wire. It is being used to go from truck through trailer tongue, then mating with the Hopkins 25' wire roll, on back to the lights. I've used this dealer before, and always get what I want. My complaints are how much they charge for shipping and the amount of time they took for me to receive it. 411664

Everythings working as it should. No complaints.
JimBo - 07/27/2018


- HM38168

Good price, and it works 399298

Thanks John b for the great review and rating!! Hopkins appreciates your business.
Hopkins C from - 07/05/2017


- HM38168

Exactly what I ordered and exactly what I needed! 395907

Hopkins appreciates your business, Heidi and we are grateful you purchased our Trailer Connector. If you have any concerns or questions, please get in contact with etrailer customer service. Thank you!
Hopkins C from - 06/23/2017


- HM38168

Ordered a bunch of stuff for hooking up a towed. Everything arrived as ordered and quick shipping. Everything fit the application without much trouble. Communication from etrailer was excellent. I would purchase from etrailer again. 372340

Steve G, I see by your comments that you did order a bunch of stuff!! If you should have any questions or problems please feel free to contact the etrailer customer service department. Thanks for being such a good customer.
Hopkins C from - 04/26/2017


- HM38168

As advertised. Worked well 351897

- HM38168

Exactly what it is supposed to be. Simple item. Nice to have choices on length. I can usually find whatever trailer part I need on Etrailer. 292529

- HM38168

Timely service. Product works as expec ted. 273705


Ask the Experts about this Hopkins Wiring

  • Towing a Trailer with a 4-Way Trailer Connector with a Vehicle that has a 5-Way Connector
    It sounds like you're trying to tow a trailer that has a 4-way connector, like part # HM38168, with a vehicle that has a 5-way connector, like part # HM37908. If this is the case you don't need any additional parts or a converter. A 4-way and 5-way will plug into each other you just won't have the 5th pin connected. Nor will you have the function that's carried on that pin. If this isn't what you're trying to do then let me know your exact set up so I can be more help.
    view full answer...
  • Will Hopkins Wiring Harness with 4-Pole Flat Trailer Connector Plug Into a Hopkins 4/7-Way Connector
    Yes, the Hopkins Wiring Harness with 4-Pole Flat Trailer Connector # HM38168 will plug into the 4-Way receptacle on your truck. Sometimes we see some compatibility issues with 4-Way flat connectors but it is rare and you would not have to worry about that since both this part and the 4-Way on your truck are made by Hopkins. I have included a link to a video review of the 4-Way for you.
    view full answer...
  • Is There a License Plate Bracket for the Thule T2 Pro XT Bike Rack
    To add a license plate bracket to any bike rack will require you to modify the bike rack. If you are willing to do that with the Thule T2 Pro XT2, # TH9034XT Black or # TH9034XTS Silver, then your best bet would be a bracket with a light in the event that you are carrying your bikes at night. I recommend the Optronics License Plate Light w/ Mounting Bracket # LP55CB. To provide power to the light the easiest thing to do would be to install the T-One # 118467 which is a plug-in wiring...
    view full answer...
  • License Plate Relocation Bracket for Viking Solutions Stack Rack II 2-Level Cargo Carrier
    It is good to note that when using a hitch mounted accessory like the Viking Solutions Stack Rack II 2-Level Cargo Carrier # 310-VSR201, that your license plate will be hidden when you have cargo loaded up. While Viking Solutions doesn't have a kit dedicated to relocating your license plate, we do have some options here at etrailer. I recommend either using the Mount Bracket # LP10SB or # LP5SB for your application. You will have to drill holes through the carrier, but after you do so...
    view full answer...
  • Towing Motorcycle Trailer w/ 5-pin Trailer Connector Using Vehicle with 4-Pin Flat Trailer Connector
    A co-worker and I cobbled something together a few years ago that we called the Frankenadapter. It would consist of the # 118158 Vehicle to Vehicle Taillight Converter, a 4-pole trailer-side connector like # HM38168 and a 5 pin round vehicle side connector like # PK11502. The adapter would be constructed as shown in the provided photo. The 5 pin connector would connect to the wires shown to the right. The adapter will separate the stop lamp signal from the right and left turn signals...
    view full answer...
  • LED Combination Trailer Light Recommendation For Hitch-Mounted 4-Bike Rack
    You can use 2 right hand combination tail lights for your bike rack. Not all of the features you mentioned may be available. One of the lights I recommend you check out is the Optronics LED Trailer Light, part # STL56RB. This light is not a low profile but it does have the 2 inch spacing for mounting you mentioned. It also has 18 diodes. The light measures 6-1/16 inches wide, 3-5/8 inches tall and it is 2-1/4 inches deep. This lamp would work for you, but keep in mind that the lamps...
    view full answer...
  • Replacement Trailer Connector with 8 Wires for a Boat Trailer
    A 4-flat trailer connector is responsible for carrying four functions which are usually brake, left turn, right turn, and tail lights. I am not familiar with a 4-way trailer connector that uses 8 wires as I do not see what the other wires could be for. The best way to determine the correct replacement would be to test each of the wires for function with a circuit tester and then replace the connector with the one that has the slots for the functions you need. It may be that instead of splicing...
    view full answer...
  • How to Attach a Trailer with a Separate 6-Way Harness to a Vehicle with a Combined 4-Way Harness
    In order to allow for the 4-way trailer connector on your Jeep to operate the lights on your trailer you will first need to install a converter box on the trailer like part # C56196 which will combine the brake and turn signals. You will then need to install a male 4-way trailer connector like part # HM38168 on the trailer that will attach to the opposite end of the converter box. In order to make these connections I recommend using part # DW05744-10. In order to allow for the 6-way...
    view full answer...

  • Why etrailer.com?

    At etrailer.com we guarantee:
  • Highest quality wiring for the best price.

    Our Lowest Price Pledge ensures you will never overpay for the parts you need.
  • Real product know-how.

    We make sure that the products we sell are what we say they are, and that they work the way they are supposed to work. Get real advice from a real person who has the knowledge and expertise needed to solve your problem.
  • Most detailed, accurate wiring information available.

    Because we take providing accurate product information seriously, we take our own detailed product photos, demo videos and installation videos, as well as verify measurements, instructions, and vehicle fit information.
  • Installations, made easy.

    We love helping people and have the most highly-trained customer service, hands-on experience, step by step videos and installation instructions.
  • Fast shipping.

    Your order is automatically routed to get out of our warehouse and to your door as quickly as possible. Receive free shipping on orders over $99.
  • Personalized service for life.

    We provide one-on-one, personalized service from the ordering process through the life of your product.
  • Trusted since 1946.

    We've been serving customers since our parts store first opened in 1946 and continue to be recognized by our customers, our vendors and third parties for exceptional service.
  • Returns Policy

    Need to return an item? No problem. Please read our Returns Policy for more information.

Info for this part was:

Edited by:
Lindsey S
Expert Research:
Michael H
Installed by:
Cole B
Written by:
Alexander C

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.

Product Experts Available Now!
Call 800-298-8924