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Adapter 7-Pole to 4-Pole and 5-Pole

Adapter 7-Pole to 4-Pole and 5-Pole

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Adapter 7-Pole to 4-Pole and 5-Pole Multi-Function Adapter 37385
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Great Prices for the best trailer wiring from Hopkins. Adapter 7-Pole to 4-Pole and 5-Pole part number 37385 can be ordered online at or call 1-800-940-8924 for expert service.
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Hopkins Trailer Wiring

  • Wiring Adapters
  • Multi-Function Adapter
  • 4 Flat
  • 5 Flat
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  • 7 Round - Blade
  • Hopkins


  • Wiring Adapter - converts the 7-way trailer connector on the vehicle to a 4-way or 5-way connector to match the trailer

If your truck has the connector on the left, and your trailer has one of the connectors on the right, you will want this adapter.
30300 18004
Vehicle End Trailer Ends

47385 Adapter 7 Pole to 4 Pole and 5 Pole - TAP # 37385

Item # 37385

California residents: click here

Video of Adapter 7-Pole to 4-Pole and 5-Pole

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

Video Transcript for Hopkins 7-Pole to 4-Pole and 5-Pole Adapter Review

Hey everybody, Ryan here at etrailer. Today we're gonna be checking out the Hopkins trailer wiring adaptor plug. So this is gonna go from a seven-way round not only to a four-way flat, but also a five-way flat. So let's check it out. And if your vehicle has a seven-way round type connector like mine does here, and you have to tow a trailer that has a four-way flat or five-way flat, this is gonna allow you to do that. So the way this will work is you'll plug into your seven-way round connector and then choose the appropriate type of wiring.

So we're hooked up to a small little fishing boat here. It has a four-way flat. We can open up that cap, take our trailer wiring, and plug right into it, and that's gonna allow all the signals to transfer back to our trailer, giving us all the lighting signals to keep us safe and legal. And what a lot of people like about this one is this honestly gives you the ability to tow or hook up to, wiring-wise, just about any trailer. So let's say maybe you have a utility trailer that has a four-way flat and then maybe a boat trailer that has brakes or something on it that has a five-way flat.

Having this one adapter is gonna allow you to pair up to all those different types and not have to keep two or three of these rolling around in your glove box or whatever the case is. These signals that this is gonna send back for our four-way flat will be your taillights, your brake lights, and your turn signals. So you have all your bases covered there. Five-way flat is gonna send out all those same lighting functions except that fifth pen is gonna be for a reverse light or backup circuit. Generally you'd see that on marine or boat trailers that are a little bit larger that have surge brakes, or even if maybe you have a utility trailer and you want to set up reverse lights on it, something along those lines.

That's where the five-way flat is gonna come into play. As far as the construction quality goes, I feel like it's pretty well-made. Feels like it's thick plastic, don't feel like a piece of junk by any means. It does fit nice and tight, at least into my seven-way. So that's good.

You know, don't worry about it having a loose connection or something, but I like how they give you the caps too because if you want to leave this thing in here, say if you tow a lot or something, or just don't feel like storing it inside the vehicle, at least you can keep those terminals protected against corrosion and whatnot. And honestly, from time to time anyway, it's not a bad idea to apply di-electric grease to 'em. And that holds true for your trailer end as well. Just keeps it in better shape and you can expect to get a little more life out of it. Something that I have ran into the past with using certain types of adapters is every trailer end might be a little bit different. These you don't see too often, but they are out there where they're kind of boxed in and in the past I've had issues getting 'em to hook up. And with this particular one, that's really not the case. It still fits right over it and creates a good tight seal. We do have a trailer here that has a five-way flat. And just to kind of show that off, you don't want to give the four-way all the love today. We'll just show you how it works too. You know, pretty standard connector and don't run into any issues in terms of getting that plugged in into our adapter plug. Other than that, at the end of the day, you know a great solution for those of you that have different types of trailers or different types of wiring, or if you're just unsure of what you might be pulling in the future. This is gonna allow you to hook up to all those different types for the most part. So can't really ask for too much more. But that'll about do it for our look-at of the Hopkins seven to five and four-way adaptor plug.

Customer Satisfaction Score:

Customer Reviews

Adapter 7-Pole to 4-Pole and 5-Pole - 37385

Average Customer Rating:  4.8 out of 5 stars   (115 Customer Reviews)


The 4/5 flat adapter arrived as described. Very good quality.


You don’t often run into a flat 5-pole connector, but it’s nice to have it covered!


Wish I would have found this earlier, Super addition to my towing kit in my Atlas


Great service.


In my quest for a 7 pin to 4 pin connector to operate lights on my luggage rack my search led me to etrailer. Initially I spoke with Derek who was very helpful and sent me a connector that was 7 to 5 pin as that's what I thought I had. Turns out I was wrong so I called back to order a 7 to 4. This time I found Ashley and she quickly mailed me the 7 to 4.
These two employees were most helpful and very courteous in my dealings with them I'm happy to recommend etrailer for these kinds of products. Give them a try!

Jim L.


Works fine. Only used it a few times but no problems.


These plugs work great. I use it for my boat trailer (5 Plug), Jetski trailer (4 Plug) and a Car Hauler Trailer (7-way). Very simple to use. Highly recommend it you use multiple trailers with different plugs and braking systems.



Everything is still working great with no issues!!


Product was delivered in a timely fashion and matched the part ordered. Quality was excellent and provided the features per price point that was desired. So far, no problems in use. It is now part of my basic trailering kit. Other products are available that have more features but they are larger and cost more. For my use this is right on. Product support and useful information from etrailer is consistently excellent.



After one year the wiring adapter continues to work well. I would not change my original review.


Works well.


Provides a quick and simple solution for connecting a trailer with a flat-4 or flat-5 plug to my truck with its round 7-way plug.

Robin N.


We recently towed a rental trailer from Maryland to New Mexico. This connector worked perfectly!


Exact replacement for the one I lost, had no problem finding it at etrailer since I had previously bought hard to find parts I needed when replacing worn parts on my boat trailer. Thanks etrailer.



Working great, I am causious about not losing it again, thanks again.


Well made and reasonably priced.


The adapter fit tightly and worked well. Be careful attaching and detaching the trailer harness so, you don't bend the bottom metal, male connector.

Everything installed correctly the first time and worked on my 2011 Honda Pilot. What a relief. It took me about 2.5 hrs because, I had to figure out fasteners for the bumper, existing wiring harness, etc. so I didn't break anything. Make sure you have a center punch, sharp metal drill bits and oil to pilot holes for self tapping screws. I am very happy with the harness and adapter.


Was exited when I found this on etrailer's website...I have 2 different trailers with 2 differents light harness connectors. This works need to switch out or have two or more adaptors in truck!! Highly recommend!


It was great and worked exactly as it was supposed to until my dog pulled it out of the receptacle and chewed it to bits.
I put an external tire carrier on my car and was using the three hole side to power my relocated license plate.
The rig lasted through all sorts of weather and terrain like a champ. I got about 9 months out of it before it was devoured. I'm sure it would have lasted for years if not for the >-< dog.


Overall...much better than going through the dealership for the sake of time and money. The online videos hit all they key points and steps bit there was some mechanical ingenuity required on my part. Mounting the bracket was the most challenging part to install and it was correctly represented in other reviews.

Personally, I wanted the 7 pin connector flush to the bumper and had to bend the mounting bracket and cut out the plastic bumper to get a tight fit. Looking back however, I think that if I would have cut out just enough of the bumper to accommodate the angle of the mounting bracket (when attached to the frame) then I would have still achieved both a solid connection and clean, professional look.

All in all, I'm very satisfied with the product and instructions received from e Trailer and staff.


As always, product arrived quickly and well-packed. Good quality and is working well on my vehicle. etrailer can be counted on for quality and customer service.



No problems, never give it a second thought. Can depend on it to do the job.


This adapter works perfect. It easily installs into the round 7 pin connector. The connector worked as all lights were lit and I was able to back my boat trailer into position with no problems. The 5 flat is used for the inclusion of the surge brakes on my boat trailer. I would recommend this to anyone needing the conversion adapter.


Good product. Works well and is very convenient to have both 4 and 5 pin connectors. Only issue is dust cover on 5 pin sticks to ground pin when you pull it off with the tab and can bend the ground pin.


The wiring kit fits perfectly. I had a small problem with the operation of the brakes on my trailer but a quick call to the great service department and my problem was quickly rectified. I will do business again.


The Adapter made a quick and easy connection between my truck and the trailer. All lights functioned properly.

Great adapter at a great price.


I'm not one to take the time to write reviews but I just got to say this company really impressed me with the information available on their site and with the terrific service when calling them on the phone. In my experience this level of customer service is very hard to find today. Keep up the great work and thanks again for your time and help. I'll definitely recommend you and will be back should I have any needs in the future!


Just what I needed, have a boat and two wheel trailer with different plugs , ordered the weather tech mud flats also for my 2011 gmc 1500, they were easy to install and look great, all items where to me in three days. Great job etrailer


Fits the round plug on the vehicle perfectly. Haven't hooked it up to the flat wire yet, but assume it should be fine. Getting this adapter with the covers for the 4 & 5 flat is absolutely the right way to go. I'm towing a 5500 lb boat with surge brakes.
Jesse did an outstanding job of helping me.


I find this adaptor to be very useful as I own and frequently tow, different size trailers all with different plug connectors. Nothing is worse than not having the right connection to make your trailer connection.


This trailer light adapter allows me to haul 2 different trailer with one vehicle. Delivery was in 3 days and I also purchased a 5 wire trailer wiring harness to match

Show More Reviews

See what our Experts say about this Hopkins Trailer Wiring

  • Will 7-Way to 5-Way Adapter Part AT75TB Work with 4-Way Connectors as Well
    Yes, the A75TB, 7-Way to 5-Way adapter will also work with 4-Way connectors. It will leave the 5th pin exposed which can cause corrosion if you will be towing in the rain. Part # 37385 is another option. It has both a 5-Way and a 4-Way with covers to protect them from corrosion.
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  • Trailer Lights Work when Vehicle Is Off, But Do Not Work When Vehicle is On
    That is interesting. What about testing the 4-Way without the hazards on. Instead, have a friend sit in the vehicle and operate each light function with the vehicle off and with the vehicle on. It could be an issue with just the hazards on. I have included a link to a help article that explains how you can go about troubleshooting the trailer wiring. If it is a bad ground, Ground problems normally show up when there is more draw on a system such as when you have the running lights on...
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  • Can a 4, 5, and 7-Way Be Installed on a 2012 Honda Pilot Using Trailer Wiring Harness 118265
    If you wanted to permanently install a 7-, 4-, and 5-Way vehicle side trailer connector to work with harness # 118265 you will have to hardwire in # HM48470. But you would have to cut off the end of the # 118265 harness that plugs into its 7-Way and hardwire in the wires by function to # HM48470. An easier option is to keep the 7-Way that came with the wiring harness for your Honda Pilot and when you need to tow a trailer with a 4 or 5-Way then use a simple adapter, # 37385.
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  • How to Get Brake Light Separate from Turn Signals on Trailer Wiring for Third Brake Light
    Typically motorcycle wiring has the brake lights and the turn signals on separate wires which is the opposite of trailer wiring which has them on the same circuit. Since you have combined circuits that you want to be separate for the third brake light to illuminate you'd need a converter like # 118158 and you'd be set.
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    Looks like you have a mid-2000's Dodge Ram truck which uses a TIPM setup for controlling the trailer taillights. This is similar to a fuse box or relay box but only Dodge can service it. When you short out the TIPM you have to take it to a dealer so that they can reset it, and they will only do this so many times before you have to spend a ton of money to replace it. The best way around the TIPM is to bypass it all together with the trailer wiring. For that you can use the wiring harness...
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  • Multiple Trailers Right Brake Lights and Turn Signals Not Working with 2003 Chevy Tahoe
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  • Troubleshooting Trailer Running Lights
    It sounds like you may have an issue with a ground wire, but there are a couple of other things to check first. I recommend using a circuit tester like the Circuit Tester Kit # PTW2993 to test your 4-way adapter. You will want to check the adapter for each function. I have included a picture to illustrate where each function is on the 4-way. If the 4-way checks out ok, you will want to check to make sure it is properly grounded. Start with the main ground on the trailer side, it should...
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    Image 1 for
  • Setting Up a 1999 Ford F-350 To Tow Trailers with 4-, 5-, 6-, and 7-Way Connectors
    There are adapters for stepping trailer connectors down like going from a 7-Way to a 6-Way, but going the other way requires extra wiring. The simplest way for you to set up your truck to be able to tow 7,6,5 and 4-Way trailer connectors is to start with a 7-Way and use adapters when necessary. Fortunately, the 99-01 Super Duty trucks from Ford are pre-wired to support all 7 functions and there is a simple plug and play 7-Way that will get your truck set up with a fully functional 7-Way...
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  • Troubleshooting Trailer Turn Signals that Work with Headlights Off But not On
    It sounds like the wiring of your trailer is at fault based on what you described. It sounds like your brake/turn signal functions are run to the running light circuit of your trailer. However, you should first test the wiring of your vehicle to make sure the problem is on the trailer side. 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....
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  • What is the 5th Pole Used for in 7-Way to 5/4-Way Adpater 37385
    The fifth pole on 7-Way to 5/4-Way adapter is not wired for electric brakes. It is wired for reverse lights.
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  • How To Wire For Lockout On Titan Coupler To Vehicle With 7-Way And Trailer With 4-Flat
    To connect the electric lockout on the Dexter Trailer Coupler, # 099-175-20, to your truck you will need to make sure the center pole of the 7-Way connector on your vehicle is wired to the reverse light circuit. If it is not wired to the reverse light circuit you will need to splice into the reverse light circuit behind the vehicles taillights and wire to the center pole inside your 7-Way vehicle connector. Once the 7-Way connector has the reverse light circuit at the center pole then...
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  • Troubleshooting Trailer Taillights that Don't Work Right When Vehicle Headlights are On
    The problem you are having is indicative of a bad ground connection. Ground issues usually show up when there is more load on the system. In this case the constant draw of the head lights is causing too much power draw for the weak ground when you try to use another function. Make sure that the main trailer connector ground and the grounds for all of the lights are attached to clean and corrosion free bare metal surface. Anything placed between a ground wire and the metal frame can interrupt...
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  • Troubleshooting Trailer Brake Lights that Dont Function
    The first thing I would check would be the left/brake and right/brake circuits of the trailer connector that is on your vehicle. You will want to use a circuit tester like our part # PTW2993 to test for voltage when the brakes are applied. If there is voltage there with the brakes applied then you know the problem lies in the trailer wiring, and it most likely is that there is a ground problem on the trailer wiring. You will want to check the wiring of your trailer for loose wiring, corrosion...
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  • Troubleshooting Lack Of Power To The Running Light 7-Way Pin On A 2012 Ford F-250
    Hey Cody, The fuse diagram I'm seeing online lists the trailer running lights have a fuse in position 26 and relay in position 29. This diagram could be wrong but definitely worth checking with the diagram on the fuse block cover to see if it's the same function. As for testing the control module, you need to reach out to Ford directly for a wiring diagram, otherwise you'll just have to trace the wiring from the fuse block to wherever the module is located and then test the wires coming...
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  • Troubleshooting Trailer Brake Lights that Don't Function With Headlights or Running Lights On
    This sounds like a ground issue. Ground problems normally show up when there is more draw on a system such as when you have the running lights on and then use another function like a turn signal or brake light. Make sure that the vehicle side and trailer side connectors are clean and free of corrosion inside and out. The main connector grounds should be attached to clean and corrosion free bare metal surfaces. The light grounds should also be attached to clean and corrosion free bare...
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  • Troubleshooting Brake Lights On Trailer Not Working But All Other Lights Work
    Since you have already found that the issue is with your truck and not the trailer you will need to check the fuses as more than likely the fuse for this function of the towing package is blown. The only other two options are all on the trailer, being a bad ground or the brake lights pulling too much power, but since the trailer works perfect with other trucks the issue will be a fuse. I included a link to a helpful article on trailer wiring for you to take a look at.
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  • Converting a 4-Way Flat to a 5-Way Flat Trailer Connector on a 2006 Toyota Sequoia
    There are a couple of ways you could add a 5-Way flat to your 2006 Toyota Sequoia. I recommend a more direct method. You can use the Adapter 4 Pole to 5 Pole Trailer Wiring Adapter, # 20036. One end plugs into the 5-Way on the boat trailer, the other end plugs into the 4-Way on the vehicle. The 4-Way end has an additional wire for the extra function that is on the 5-Way end. If the extra pin on the trailer is used for an electric reverse lockout, you would connect the blue wire to the...
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  • Trailer Brake and Turn Signals Not Working When Connected to a 2008 Ford F-250
    There is a fuse for the trailer stop/turn relay on the 2008 Ford F-250 in location 34 under the hood. The relays are in location 20 and 21 and the easiest way to test those is to use a known good relay in place of a potential bad one. But it might not even be an issue on the truck side. To know for sure where the problem is coming from you can use a circuit tester such as # PTW2993 or a meter if you have one to test the connector on your truck. If the turn signal and brake lights are working...
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    The interior dome light in a trailer will either be powered directly from the trailer battery which means there would be no fuse on the tow vehicle for this or it will be hooked up to the 12 volt battery charge power circuit. If you have the former then you will need to trace the power wire from the light to the battery as this will then lead you to an in-line fuse or broken wire. If you have the latter then the fuse you will need to check on a 2014 Ford F-150 is in the engine bay fuse...
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  • No Turn or Brake Signals While Towing With 2018 Ford F-150 After New 7-Way Installation
    When you say receiver I believe you mean a trailer wiring connector. The trailer connector does need to be grounded to a clean bare metal surface of the truck's frame which is most likely causing the issues with the lights. Another thing to check for is any corrosion on the pins or bent pins of the trailer connector which may be causing a bad connection. If there is corrosion you can lightly sand it off but it sounds like you have a classic ground issue especially since you said the trailer...
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  • Will The 7 Pole to 4 Pole Adapter Fit My 2007 Toyota Tacoma
    The adapter that you have selected, Adapter 7 pole to 4 Pole and 5 Pole, part # 37385 will work perfectly for your 2007 Toyota Tacoma with 7 way plug. It will convert your 7-way to a 4-way or 5-way with your flat trailer connector.
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  • Troubleshooting Brake Light/Left Turn Signal on a Trailer Towed by 1999 Chevrolet Silverado
    The first thing I would test is the trailer connector on your 1999 Chevrolet Silverado using a circuit tester like part # PTW2993 to see if the problem lies in the trailer or in your vehicle. See the linked video to see how to do this. You will be testing for brake/stop light functionality of the circuit and this will tell you if the problem is on the truck or the trailer. Also, to ensure that your trailer connector is wired properly, we recommend using the circuit tester to match pins...
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  • Low Beam Headlight Not Working But High Beam Does Work
    It sounds like there could be a fuse blown or damage or corrosion in the bulb socket. Bulbs that have both high and low beam functions have 2 filaments in them so it is also possible that the low beam filament has burned out. If you can tell me the year, make, and model of the vehicle I can recommend some replacement bulbs.
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