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Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter
(70 reviews)
Price: $37.72
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Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter
Part Number: 37175
In Stock
$37.72
Retail:$42.69
You Save: 12%
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- Reviews (70)
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Hopkins Custom Fit Vehicle Wiring - 37175
Highlights
- Tow More Trailer Types: 4-flat to 6-round adapter lets you connect different trailer plugs.
- Brake Controller Ready: Blue wire carries brake signal for electric trailer brakes.
- Charge or Power Gear: 10-gauge black lead supports 12V auxiliary or battery charge line.
- Solid Grounding: White wire connects to frame for reliable circuit grounding.
- Dual Connector Access: Built-in 4-way and 6-way sockets let you tow with either plug style.
Features to know about
Adds 6-Way Round Connection Without Rewiring: 4-Flat to 6-Round Adapter
If your vehicle has a 4-way flat but your trailer uses a 6-way round plug, this adapter makes them work together instantly. The Hopkins Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter plugs into the existing 4-flat connector and gives you both a 4-flat and a 6-round at the back of your vehicle. It’s a quick, plug-in solution for connecting trailers with different wiring styles.
Expands Functionality When You Need More Circuits: Extra Leads for Power and Brakes
The adapter includes three loose wire leads so you can add more functions when needed. The white wire grounds to the frame, while the blue wire handles brake controller output and the black wire supplies 12-volt auxiliary power. When hooked up through a 40-amp circuit breaker, the black lead can charge a trailer battery or power accessories. The setup uses 10-gauge wire for each of these circuits, ensuring solid current handling when you expand your wiring later.
Keeps Towing Options Open: Dual Connector Design
With both a 6-round and a standard 4-flat plug built into one housing, you don’t have to switch cords or adapters every time you hook up a different trailer. Whether you’re pulling a simple utility trailer or one equipped with brakes or onboard power, this dual connector keeps your rig ready for either type.
Simple, Durable Connection Every Time: Tight-Fit Design with Protective Cover
The snug-fitting connector makes a solid link to your existing 4-way without play or looseness. A protective cover on the round socket shields the terminals from dirt and moisture when not in use, keeping corrosion out so it stays reliable season after season.
Specs
Electrical Specifications
- Wire Gauge: 10 gauge (blue wire, red wire, and black wire)
47175 Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter
Video of Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter
Videos are provided as a guide only. Refer to manufacturer installation instructions and specs for complete information.
Video Transcript for Test Fit: Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter on a 2008 Chevrolet Express Van
Today on this 2008 Chevrolet Express we are going to install part number 37175 from Hopkins. What this is is a 4-pole to 6-pole and 4-pole adapter. It will install on the existing 4-pole that is on the vehicle and convert it. The first thing we are going to do is tidy up the wires. We are just going to use some electric tape to secure everything together. While we are at it, we will go ahead and show you the functions of the wires. First off we will cover the function of the wires. This is the 4-pole itself and this will plug in to the 4-pole that is already existing on the vehicle. The white wire is the ground and that will get connected to the frame. And then we have the red and blue wires. Traditionally, blue is for brakes. However, on this particular 6-pole, the blue wire is ran to the center pin. So a lot of times the outside pin is going to be for brakes. It just depends on how your trailer is wired up. The red wire here is typically used for a hot lead. However, this is run to the outside pin. So you can actually use either one of these for the hot lead for 12 volts or brake lead, depending on how your trailer is wired up. On this install, we are actually not going to be using these. We are just going to use the 6-pole for lights only. 1:09
OK, here we are all finished. Let us go ahead and set this to the side and go ahead and install the bracket on to the bumper of the vehicle. We are going to take our bracket and install it right on the bottom edge of the bumper. We are going to use a set of vice grips to go ahead and just clamp it into place. Get it straight with the hitch. Alright, then we will go ahead and use some self-tapping screws to go ahead and attach it. Now we will go ahead and install our wire harness. Push it into place and then attach it with the existing hardware. Now we are going to take the 4-pole that is already installed on the vehicle and we will plug these two together. Now it is a good idea to use some dielectric grease to help protect the contacts. This will end up being a permanent connection when it is all done. And then we will thread a zip-tie around it. Now our two other ends that are not going to be used, we will just cover those with electric tape as well so they will be safe for future use. OK, now we will take our white wire. What I think we will do is just go ahead and push it inside of the frame. And then we will actually attach it to the bottom of the frame behind the hitch. We will go ahead and zip-tie our wires to take up the excess slack. There is a nice little hole in the frame here, so we will use that. Alright, with that that finishes our install. One other thing you might want to do is go ahead and test it with a light tester and make sure everything is functioning. And then try it on your trailer. And that will finish it for part number 37175 from Hopkins.
Customer Satisfaction Score:
89% were satisfied with this product
11% of customers were not satisfied
- Product did not meet expectations
- Wrong item was ordered
- Did not arrive in time
Ratings & Reviews
4.7
70 reviews
by:
Dan
05/20/2026
Great product and customer service. Fast shipping and easy install! I highly recommend e-trailer and have been using them for many years now!
by:
Matt
04/27/2022
This adapter really cleaned up the installation and connected directly to the wiring harness. Maybe added an additional 20 mins to install this adapter but totally worth the time and money.
by:
Ed
06/26/2019
II use it on my towed vehicle behind the motor home. It allows me to take motor home power to a trickle charger in the towed vehicle and connect to the towed vehicle wiring. The four prong receptacle provides outlet to be used if there is ever in need for a four prong fitting good.
by:
Robert
06/28/2025
I love these connectors. I’ve been using them for years.
by:
Jerry
06/13/2019
Pulled our popup camper all over Michigan from Tawas to Drummond Island with no hickups with lighting. We also pull a smaller trailer with the four prong plug, also with no problems. Its nice that these plugs stay covered so as to not let salt/grime into plugins. Great products in my opinion. Had for just over one year with no problems at all. We had these installed by local reliable installers and wouldn't change anything.
by:
Dave S
11/25/2016
Draw-Tite 75726 hitch fit perfectly and looks great.
Instructions from manufacturer regarding 2013 Highlander driver's side splash panel removal and then not use: it was easy to cut an 8" longer slot in the splash panel and reinstall, which retains the bumper and fender integrity.
The 37175 4 & 6 pole adapter is a clean look and very handy using the different trailer hookups.
The 118449 T wire harness hookup is a no hassle, no brainer and works perfectly
Etrailer will my business on my next vehicle needing towing equipment!
Instructions from manufacturer regarding 2013 Highlander driver's side splash panel removal and then not use: it was easy to cut an 8" longer slot in the splash panel and reinstall, which retains the bumper and fender integrity.
The 37175 4 & 6 pole adapter is a clean look and very handy using the different trailer hookups.
The 118449 T wire harness hookup is a no hassle, no brainer and works perfectly
Etrailer will my business on my next vehicle needing towing equipment!
by:
Tony B.
05/09/2015
The adapter was easy to install and looks great on my 2011 Toyota Corolla. It allows me to tow my small motorcycle camper and my utility trailer with the car, truck or the motorcycle without changing the existing wiring on either one. Etrailer shipped the order in very good time and kept me informed of the order status until it arrived a my door.
by:
Randy
04/30/2025
Was what I ordered, shipping was good. Spring on cover would not hold cover down. Had to take apart and bend spring.
by:
Brad D
11/15/2020
This item was used to reair an existing unit mounted on my Toyota Tacoma. Although it initially worked very well I thought the 4 pole connector was not sturdy enough for my use. After having a pin break out when the plug was snagged I changed to the 6 pole connector and have been very satisfied.
by:
Bruce T.
03/02/2017
This should have been an easy install, but it wasn't. There is nothing wrong with the part and should work well in most situations. However, in my situation, I installed the Curt Class III custom hitch which allows for keeping the full size spare tire. Unfortunately for installing this part, there was no room if the mounting bracket was used - the hitch was in the way.
So, I drilled a hole through the bumper and installed it there. This took more time than the instructed install, but in the end it works great and there is no worry of wires rubbing or wearing through. See picture.
So, I drilled a hole through the bumper and installed it there. This took more time than the instructed install, but in the end it works great and there is no worry of wires rubbing or wearing through. See picture.
by:
Travis
08/24/2016
We have had our hitch and wiring harness for about a year now and its still performing great. This site sells great products and we will definitely be back to buy more when ever we need it!
by:
Carl D
02/27/2012
bumper I bought after someone collided with my factory bumper (thank you very much whoever you were). Installation was a snap into the pre-drilled hole in the bumper. Just used some dielectric grease on the contacts, wrapped with electric tape, zip-tied to secure, and did a quick tap into the frame for the ground.
by:
Jonathan J.
04/21/2015
Product was easy to install. Comes with bracket, which is nice, but I didn't use, had a place already built in to the hitch. Had it installed in less than 10 minutes. e-trailer kept me informed through the whole shipping process, and they have great how-to videos.
by:
Richard C.
09/11/2011
general hookup kit as it provides wiring options for different trailers and is very simple to install, including excellent instructions. I highly recommend this kit.
by:
John T
04/30/2012
The product I ordered shipped out on time and arrived in good condition. The folks at ETrailer set me out a shipping tracker and notifcation.....very helpful! I would recommend ETrailer to anyone looking for trailer parts or accesories. Products are high quality and prices are great! Keep up the good work!
by:
Tim
03/21/2026
I’ve sent an email asking how to return to exchange for a different plug and haven’t received any response
Mike L.
3/23/2026
Sorry about that, Tim. I'll get that taken care of for you.
by:
DRid
08/05/2015
Ordered a 4 to 6 pole trailer wiring adapter. It was perfect, as was the service, delivery time and follow up.
by:
Michael
06/07/2019
Great product that works well with the standard wiring harness for the car. This worked great with my 1963 Aloha trailer that uses the 6 pin configuration.
by:
Keith
02/28/2019
Works like a charm. Wired to connect to motorhome. All features working.
Keith C.
3/1/2020
Installed it, connected it, its working just as it should
by:
kyle
11/15/2016
the wiring works fine but the spring does not hold the cover closed on the 6 pole side. i tried bending the spring but when you open it up it re bends the spring. mine could have been a defect but would have given 5 stars if it wasn't for the spring
by:
Ron
07/01/2019
This product is great and works good, easy to install, fits ext. wire harness like a glove.
by:
Steve
04/18/2019
eTrailer is a great company that sells good products at a reasonable price. In addition, they are very helpful in selecting products and providing post sale support. As for the product... it’s just what I was looking for. Perfect!
by:
Ned
04/01/2020
This was the perfect harness for my vehicle. Installed easily and has made a great deal of difference. Excellent customer service as well.
by:
Tom C.
02/26/2017
fast shipping and products as described, great company will use in the future and have already told friends.
by:
Paul S
06/18/2015
This plug is exactly what I needed. And for a good price. Easy installation. Saves the work of having to do all the wiring when I already have a flat 4 plug
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See what our Experts say about this Hopkins Custom Fit Vehicle Wiring
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view full answer... - Recommended Adapter for trailer 6-Way to Vehicle 4-WayHey Saran, thanks for reaching out! For a direct part that works with your setup you'll need the Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175. While this does work, what I recommend doing is installing the Adapter 4-Pole to 7-Pole and 4-Pole # 37185 and using the Adapter # 47549 to make your trailer 6-Way compatible with the 7-Way on this adapter. Reason being that a 7-Way is way more common of a connection so this will help to "future-proof" your vehicle side of...
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view full answer... - Does Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175 Use 10 Gauge WireThe Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175 has 10 gauge wire for the blue wire, red wire, and black wire. The aux circuit you mentioned would be the black wire.
view full answer... - Adapter For Trailer With 6-Pin Round Plug And Vehicle With 4-Flat Hello Kevin. We do have an adapter you can use for this purpose. Take a look at the Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175. This will connect to the 4 flat plug on your car and will allow you to connect the 6-prong round plug on your boat trailer. The white ground wire will need to be grounded to the vehicle frame. You can leave the other two wires disconnected, but this will only operate the lights on the trailer.
view full answer... - Availability of 4-Way Flat to 6-Way Round AdapterHey Jesse, we do have a 4-flat to 6-round adapter with the part # 37175. This would allow the 6-way of your trailer to plug into a 4-way on a vehicle. Your other problem about the trailer wiring that is ran to your vehicle taillights is probably due to how the vehicle taillight wiring is configured. Does the vehicle have turn signals that are amber and separate from the stop lights? if so. this is true. What is the vehicle though? I can see if there's an easier 4-way solution.
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view full answer... - Parts Needed to Adapt a 4 Pin to a 6 Pin RoundYes, it is possible to change your 4 pin to a 6 pin round. I recommend using the Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175. This would allow you to have both the 4 pin and 6 pin round. I have included a video that shows an installation of the # 37175. You will want to pick up some Dielectric Grease # 11755 and the No-Drill Mount Bracket # 18136 for installation.
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- Difference Between Hopkins 4 Pole to 6 Way Trailer Connector Adapter 37175 and 47175There is no difference between the # 37175 and the 47175, it's the same exact part. Our part number for the Hopkins 4 pole to 6 way trailer connector adapter is # 37175, and Hopkins uses 47175 as the part number.
view full answer... - Wiring a Trailer with a 6-Pin Plug and Surge Brakes to a 2004 Dodge Ram with a 4-Way ConnecterTypically, a trailer with a 6-way plug has electric brakes, not surge. I would double check that you have surge brakes and that your plug is a 6-way. A 6-way plug is circular, has 5 pins on the outside and 1 pin in the middle. If you do have a 6-way with surge brakes, you will need the Adapter 4 Pole to 6 Pole, part # 37175. You will have 3 loose wires coming off of the adapter. You will ground the white, and then you will have to wire one of the two remaining wires into your reverse light....
view full answer... - Trailer Wiring Adapter Compatible With Hopkins Smart Hitch Backup Camera For 6-Pin Trailer ConnectorThe Hopkins Smart Hitch Backup Camera and Hitch Aligner System # HM50002 will only connect to a 7-Way like the Hopkins Endurance Multi-Tow 4-Way Flat to 7-Way RV Trailer Adapter # HM47180 that has a removable connector. The Adapter 4 Pole to 6 Pole and 4 Pole Trailer Wiring Adapter # 37175 does not have a removable connector and will not fit with the smart camera. You will be able to use the 7-Way Round to 6-Way Round Trailer Connector Adapter # 47549 to go from the 7-way to a 6-pin connection...
view full answer... - Where Does the Brake Controller Output Wire Terminate on a 2008 Dodge Ram without OEM 7-WayOn a 2008 Dodge Ram that did not come with a 7-Way trailer connector the brake controller output wire does not run all the way to the back of the truck. It stops at the connector that is located under the driver's side wheel well. I have linked a help article that covers this and other steps. But if you have a factory 7-Way then you would not need to worry about that because the wire would be run all the way back.
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Ed
6/27/2020
Works well but bracket is rusting