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Price: $29.11

Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps

Item # C57674

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Retail:$34.25

Our Price: $29.11

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curt wiring multi-function adapter 4 flat
curt wiring adapters 7 blade 4 flat
curt wiring adapters 4 flat adapter pole to 7 and w/test lamps
curt wiring adapters 7 blade 4 flat adapter pole to and w/test lamps
curt wiring 4 flat 7 blade c57674
curt wiring adapters multi-function adapter 4 pole to 7 and w/test lamps
curt wiring adapters 4 flat c57674
curt wiring adapters multi-function adapter

In Use/Installed

2017 chevrolet equinox wiring curt adapters 4 flat adapter pole to 7 and w/test lamps
2017 chevrolet equinox wiring curt multi-function adapter 4 flat in use
2017 chevrolet equinox wiring curt multi-function adapter 4 flat c57674
2017 chevrolet equinox wiring curt adapters 7 blade 4 flat in use
2017 chevrolet equinox wiring curt multi-function adapter 7 blade 4 flat c57674

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curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat adapter pole to 7 and w/test lamps
curt wiring multi-function adapter 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat adapter pole to 7 and w/test lamps
curt wiring multi-function adapter 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat adapter pole to 7 and w/test lamps
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat c57674
curt wiring adapters 4 flat adapter pole to 7 and w/test lamps

  • Wiring Adapters
  • Multi-Function Adapter
  • 4 Flat
  • 7 Blade
  • 4 Flat
  • Plug and Lead
  • Curt
This multi-function, vehicle-end connector converts any 4-way flat, vehicle-end plug to a combination 7-way outlet and 4-pole flat outlet. Lowest Prices for the best wiring from Curt. Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps part number C57674 can be ordered online at etrailer.com or call 800-298-8924 for expert service.



Curt Wiring - C57674

This multi-function, vehicle-end connector converts any 4-way flat, vehicle-end plug to a combination 7-way outlet and 4-pole flat outlet.


Features:

  • Adapts 4-way flat to both 7-way round and 4-way flat
  • Includes integrated test lamps which display proper connections
    • Shows if you wiring on the trailer isn't working properly - burned out bulbs, poor connection, etc.
  • Includes mounting bracket and hardware
    • Distance between vehicle mounting holes center to center: 2-1/4"


57674 Curt Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps



C57674 Installation InstructionsInstallation Details C57674 Installation instructions



Value - This item

Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps


Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps
Curt Wiring

167 reviews

Code: C57674

In Stock

Retail:$34.25

Our Price: $29.11


  • Wiring
  • Wiring Adapters
  • Multi-Function Adapter
  • 4 Flat
  • Plug and Lead
  • 7 Blade
  • 4 Flat
  • Curt


This multi-function, vehicle-end connector converts any 4-way flat, vehicle-end plug to a combination 7-way outlet and 4-pole flat outlet.

more information →
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  • Single-Function Adapter
  • 7 Blade
  • Plug Only
  • Pollak


Quickly and easily convert a 7-pole, RV-style connector to a 4-way, flat connector with this RV connector adapter. Adapter has a non-corrosive nylon shell.

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  • Hopkins


Adapter converts from 4 pole wiring on vehicle to 7-pole round plug and 4-pole flat. Additional wire leads for brake, power and accessory.

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Hopkins Endurance Multi-Tow 4-Way Flat to 7-Way RV Trailer Adapter w/ 4-Way Vehicle End Plug


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Hopkins Wiring

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  • Hopkins


Adapt a 4-way flat to a 7-way RV-style socket while still retaining use of the 4-way. Or simply replace a damaged 7-way connector. Plug into tow package for 7-way, or plug into existing 4-way and hardwire into vehicle to get additional functions.

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Video of Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps


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




Video Transcript for Curt Wiring C57674 Review

Today we're going to be reviewing part number C57674. This is the Curt Wiring Adapter from a 4 way flat to both a 7 way round and a 4 way flat. The multi function vehicle end connectors are going to convert any 4 way flat end connector vehicle plug to a combination of a 7 way outlet, and that's also going to have the 4 pole flat outlet as well. It's going to include the integrated test lamp. You can see that it's going to have the display right here which is going to display the proper connections. This is going to indicate and show if the wiring on your trailer isn't working properly.

It's going to show whether you have burned out bulbs, poor connections, things that go along with that. It's also going to include your mounting bracket and all the hardware that you need to get the socket mounted to the bracket. It's going to come with four screws and it's going to come with the washers and the nuts that you need to get the bracket . or the socket mounted to the four connections there on the mounting bracket. To go over the functions of the wires real quick. You can see here that it's going to expose a 4 way flat connector.

This is designed to plug into your existing 4 way, and then it's going to have four more wires that are exposed. All the wires are going to have butt connectors on them. The white wire's going to have a ring terminal on it for easy connection, so those are already in place, they're already installed and ready to be connected. Your white wire is going to be your ground wire. This is to be grounded to the vehicle frame. The yellow wire is going to be the center pole of the 7 way connector.

It's normally used for connection to the reverse light circuit. Your blue wire is for the connection of the electric brake feed from the brake controller. Then your black wire is going to be the twelve volt wire and will need to be ran to the positive terminal of the vehicle battery. It needs to be ran through a forty amp circuit breaker. That is going to be sold separately.

You can find that right here on our website with part number PK54540. This wire will be used to maintain the charge of a trailer mounted accessory battery and/or breakaway battery. Those already have the easy connectors on them that way all you have to do is make a few connections, get some wiring. If you need the full setup for installing a brake controller, all the additional wiring, you can use part number ETBC7. That's a kit that we here at Etrailer put together to make it easier for you. You can find that right here on our website. I want to focus here on the 7 way connector. It's got a spring loaded lid so when it's not in use it's going to remain closed that way it's going to protect the connection points on the inside. It's got the indicators here on this side. Each light has a code right next to it. The first one's going to be twelve volt. That's going to be for the twelve volt hot lead. If that's connected correctly and working properly that will light up. BK is the output from the brake controller so if you do not have a brake controller installed this light will not light up. The back up, BU, is for the reverse lights. If this circuit is not connected on the vehicle it will also not light up. RT stands for right turn. TM stands for the running lights or tail and marker lights, and then LT stands for left turn. The overall dimensions of the actual socket here is going to be . the housing that goes around the socket, that's going to give us a measurement of three and three eighths by three inches. Once you have it ready to be mounted with the bracket all you have to do is run your wires through here. It's going to fit around that socket portion back here really nicely. It's going to go right through the appropriate holes. It's going to make sure that all the mounting holes line up, and then you're going to take your 4 way flat, it's got a couple grooves on it that slide into the bracket face. Once you have those on you just push it in. It's going to hold it right there for easy connection. You're going to have your 7 way round connector right here, and then right next to it you're going to have easy access to the 4 way flat. That's going to do it for our review of part number C57674. This is the Curt Wiring Adapter converting from just your 4 way flat to both a 7 way round and a 4 way flat system. .


Customer Reviews

Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps - C57674

Average Customer Rating:  4.8 out of 5 stars   (167 Customer Reviews)

This multi-function, vehicle-end connector converts any 4-way flat, vehicle-end plug to a combination 7-way outlet and 4-pole flat outlet.

- C57674

by: Dan S.06/16/2014


Great product I used this to convert my 4-way harness to a 7-way + 4-way harness on my 2011 Toyota Sienna. Everything went really well. The only very small complaint I had about this product is the length of the white ground wire. It was too short to reach a good grounding point on the frame so I had to go buy some extra wire and connectors to extend it. Make that cable about 3 ft longer, and just provide the ring terminal and this would be a perfect product. Installing it makes me want to splurge on a tow controller and charge line... 135750


Comments

HiI have a toyota sienna 2011 and i want to tow a pop-up camper. Mine has a towing package. The camper is around 2400 lb. in your case do you think a brake controller is necesary?can you tell me What kind of cable do u buy to extend the white ground cable?Di d u buy the no drill tie bracket?

-- comment by: Aldo - 06/27/2014

5189
Comments

Aldo. We towed a popup trailer that was little less than that loaded weight without any issue. This was a one time rental for us. We towed up over Vail Pass in Colorado without any issue at all. The engine and transmission on the Sienna could tow a lot more weight, it is limited due to the suspensiontire rating.The only problem we faced is that when hitched we couldnt open the rear door of the sienna due to the trailer jack on the tongue of the trailer.If I was to tow regularly I would invest in a break controller, charge line, and a Weight Distributing Hitch. The main limitation in towing with a sienna is the hitch weight.No I didnt buy the tie bracket. The hitch I purchased 75696 had a built in bracket that this fit on perfectly just had to get a few screws/nuts for it.I just bought some 12 guauge auto wire at autozone.

-- comment by: Daniel S - 06/30/2014

5220

- C57674

by: Chris H.05/18/2013


I really liked the idea of having the LEDs to let me know if I was having any problems with the wiring harness, but I did find a problem with it. I installed the wiring harness myself, using the instructions on the website, but after connecting everything I realized that the LED for 12v power is always on. It is not switched by the key, so although an LED should have low draw, this might not be a good idea on a work truck that stays parked for long stretches. 80885


Comments

I am still very happy with this adaptor, but I did put back in the plug on my brake controller so I could unplug it when the trailer was not connected, the brake light was on, and I disconnected the continuous 12v. Also, make sure your 4 wire connector is clean or you might have dim lights. Although the LEDs are useful, I found a plug in tester to be more accurate because of the false brake signal I was getting.

Chris H - 05/19/2014

4322

- C57674

by: Bill H.12/04/2016


I installed this 4 to 7pin adapter with the T-one harness 118449 and the Drawtite hitch on my 2016 Toyota Highlander. I think the install was 1st rate. This adapter allows me to connect either a 4 pin or 7 pin plug. Nice. Very simple to check out the installation with the test lights. Adapter looks rugged and well made. The 4 pin receptacle that slides into the bracket should have better retention though. Also I provided a picture of the 4 wire cable from the car harness to the adapter as it exits the storage compartment. I removed the grommet/seal. Made an X cut in the center. Forced the cable through it. Made a waterproof seal with RTV. 322171



- C57674

by: Norm M.04/30/2013


My new Curt 4 pole to 7 pole and 4 pole adapter (C57674) with test lamps is a quality addition to compliment my Curt class III hitch. Attaching it to my '01 Blazer went smoothly, and testing to see that it was wired properly was a snap with the built in test lamps. 78432


Comments

No trouble installing. Works perfectly, except the 4 wire connector likes to come adrift, I like it very much even with that little glitch !

Norm M - 04/30/2014

3864

- C57674

by: Steve C.06/29/2015


The adapter was easy to install and works great. I really like the LED status indicators on the socket. I had the voltmeter out but didn't have to use it. 208015


Comments

Ive used the wiring harness with the 7 pin connector for your camper and it is still working great. I have borrowed a friends cargo trailer and use the 4 pin connect. It is nice not having to use an adapter.

Steve C - 06/28/2016

19001

- C57674

by: Eddy03/05/2013


Great product! Sturdy and weather-proof connections and wires! Easily installed. Thanks Curt and etrailer.com for an awesome item! 68991



- C57674

by: Richard Collette06/02/2013


The bracket was too wide for the OEM hitch and cover on a 2013 Highlander (see photo). I had to grind down part of the the bracket so it would clear the plastic cover. The top two mounting screws did not line up. I had to elongate one of the holes. The 4 pin connector merely slides into the side of the bracket, rather than fitting in like a grommet, so I'll bet it comes out one day. The wiring on the back of the 4 pin connector is visible when looking at the side of the bracket, making for a less than clean look. 82915



- C57674

by: Chris C.06/04/2014


2013 Dodge Durango Looks great. Nice and clean installation. 134266



- C57674

by: Charkeyes10/06/2014


Product is good if you are using it on a "full size vehicle". Using it for connecting to my Scion xB, was not at all what I expected or wanted. Sadly, Curt Mfg. does not have what I thought this one would do. This 4 pin connection to 4 pin and 7 pin adapter with test lights as pictured is very deceiving. Mount bracket is slotted for holding the 4 pin connection on the left side, it does not hold the connector in place securely. Wiring harness is a lot heavier and bulky, it dupicates the wiring, a pigtail to the 7 pin connector via a splicing system of wires and has an additional pigtail going separately to the 4pin connector on the mount. 154804



- C57674

by: Lawrence L08/16/2017


I recently had a receiver hitch installed on my 89 Silverado and the wiring was merely zip tied to the safety chain connection. Well that didn't sit well with me. I wanted a more permanent wiring connection point. So I purchased your 4 flat to 4 flat and 7 way plug and installed it. So far so good. The installation turned out perfect and it looks good. The test lights are a great thing as well. I couldn't be happier. 420882



- C57674

by: DWP02/21/2014


All connections worked first time. I did have to extend the white wire to make the ground connection to the frame. What I really liked was the way this adapter plugs into the tail lighting wiring. The only thing missing from this device was a stainless steel clamp. I had to use two small ones to make the attachment to the hitch. I also cut a small slot in the center of the mounting bracket to secure to the hitch. I had to move the mounting a little farther left to clear the spare tire when removing it. Still a great value for the money and the test lights worked good. 117102



- C57674

by: Jason A02/21/2017


I bought this for my '68 GMC 3/4 ton, which is in really nice shape so I wanted a clean install. The hitch was pretty easy to fit - I had to drill holes in the frame but I knew that going in. I especially liked the built-in bracket for mounting the trailer plug, worked great with a Curt combo 7 pin / 4 pin adapter from eTrailer. Good product, great seller. 346974



- C57674

by: David09/07/2017


Because of some overestimation of my own narrow skill set, and an equal overestimation of the electronics on my towing vehicle, I ended up having this professionally installed. Works great, and I would order this item again in a heart beat. I'm also terribly amused when I press the lock/unlock button on my key fob and the red LED lights fire off on the wiring harness. Makes me laugh every time. When I purchased this item, etrailer went of their way to email me with links, suggestions, videos, and images. Excellent support, and thank you. 429770



- C57674

by: Johnny11/17/2017


Great customer service on-time delivery super fast shipping product was just as described works well and just what I was looking for. 452971



- C57674

by: Ralph C.09/19/2017


Installed and have camped for one season using this 7-pin connector. Works great. I did make one mistake, I didn't add a relay to break the aux power connection when my vehicle is not running so the aux power LED is always lit. Got a number of comments about that this season. Might have to add a relay... 434040



- C57674

by: Tom H12/20/2013


Very rugged little item. I'm really glad I chose to buy two of these. My former 4 way flat had the test lights built in and this one does too. Every thing about this seems very well built. Probably made in America... or it seems like it if not. But it's not just the product that makes this nice. It's etrailer staff. They patiently took time to explain a number of things to me when I bought these and a Tekonsha brake controller. I don't even look anywhere else if I need anything. 110648



- C57674

by: Bob semrow08/01/2017


The product was great but as I read in some other review the power wire was too short and required a splice but other than that was exactly what I needed and exactly as portrayed in your video. Delivery wasn't the best...... started out from MO by UPS and was moving along nicely till it reached MT then somehow the postal service got involved and delivery was three days longer ..... and the UPS truck still went by! But, thats no reflection on you guys, you're great. 413781



- C57674

by: Norm10/23/2016


This is my second order of this trailer light hookup. This is the end that goes on your truck I was so impressed with the one I ordered for my RV, that I ordered another one for my truck. This is so easy to hookup. The bonuses are that it has a four-way on the side for older trailers and it has lights to help troubleshoot when a trailer is not wired correctly or has a loose wire. I cannot think of a better hookup, and I searched the stores for just this style. 309874



- C57674

by: Pokey5807/03/2017


This is the second vehicle I have installed this adapter on. We tow a Coleman popup and another smaller trailer so we need both the 4-pin and 7-pin adapters. The test lamps are great to confirm that you have installed the wiring correctly. 401368



- C57674

by: Steve Kady04/18/2017


I called and spoke with Yvvone about a hitch a its wiring. This lady knows her stuff. I had several questions, especially about the wiring and she was very quick in answering each one of them. She took my order and it arrived 3 days later. The customer service in this company is absolutely fantastic. They have quality products and they are priced right. It is a pleasure doing business with folks such as Yvvone and etrailer.com 369366



- C57674

by: Dave W07/20/2016


The directions were clear and the adapter performed well the first time I hooked it up. I am extremely happy with the product as well as the vast amount of resources provided by eTrailer that make self-installation by a novice such as myself less painful. It is now one year later and I recently had a wiring issue with my trailer and the built-in diagnostic lights saved a lot of extra steps in diagnosis. 274205


Comments

Great! No problems! Glad I got it from etrailer.com

David W - 07/21/2017

26439

- C57674

by: Adam01/31/2013


I need the ability to pull trailers with both 4 Pole and 7 Pole connections and this adapter did the trick. It's heavy duty and I think the extra few bucks for the Test Lamps was well worth it. 64739



- C57674

by: Chris04/28/2014


Absolutely love this adapter. I've used other ones in the past. What sets this one apart is the indicator lights of the 7-pin. It's great that you don't have to plug in a trailer to verify electrical connections are all correct, as well as, it helps in troubleshooting whether there is a problem with the vehicle or the trailer wiring. Highly recommend this! It's worth the extra couple bucks. 127684



- C57674

by: Daniel10/22/2016


Great product for a great price, it's worth mentioning though that the 7 blade and 4 blade conections don't mount side by side unless you use the supplied bracket, mounting it through a flat spot on the bumper Wil leave the 4 pin connector hanging behind where you still have to crawl underneath to hook up a small trailer. But the LED lights are absolutely awesome to have and have labled. 309755


Comments

Still works great, and the led lights are still the best feature

Daniel - 10/22/2017

29674

- C57674

by: Kyle T.07/31/2016


Pretty good adapter. Works great and looks good. Only complaint is that you have to figure out how to mount it to the vehicle by yourself but is understandable since not all vehicles will have the same attachment points. I installed onto my Dodge Durango and I was able to bolt directly to the bumper with my own bolts. Great buy. 277933



- C57674

by: Shad03/02/2016


Haven't installed it yet but I like the selection this site has for various products. Placing an order was easy and shipping was fairly quick. I do wish that this product came with installation instructions or diagrams on paper. I like to have a hard copy when installing things. It is an easier reference for me. 239248



- C57674

by: TTom R.06/13/2017


This connector is easy to install with the instructions provided. I'm an electronics technician so maybe I have a little more skill than the average guy but I'm anyone with modest skill will do fine with this item. Especially since etrailer has provided very detailed installation instructions on You Tube. 392534



- C57674

by: YOGI12/23/2015


THE ADAPTER WORKED AS THEY SAID IT WOULD ON MY DODGE 2007 RAM 1500 JUST HAD TO TRIM OUT PLASTIC ON THE SIDE OF THEY HOLE IN THE FACTORY BUMPER AFTER THAT IT FIT LIKE A GLOVE BOLTED RIGHT IN BUT I DONT HAVE THE ELECTRIC BRAKE BOX YET TO HOOK UP THE OTHER WIRES JUST YET BUT I ASSUME IT WILL WORK AS EXSPECTED 234108



- C57674

by: Mike B05/01/2012


The fit was perfect, did not require any modification to the unit or my vehicle. Took approximately 30 minutes, mainly because I was taking my time to make it look nice and I was using heat shrink connections. etrailer was outstanding in their support - as usual - and I received my package quickly. 38887



- C57674

by: Jeff02/24/2013


Thank you so much for solving a wiring issue between a very old horse trailer and my tacoma pickup. Starting from the first phone call to the delivery of a part that fit perfect! Knowledgable staff, quick delivery and a good product. In a world filled with underachievement. I will say well done. 67619



- C57674

by: Bronco07/30/2014


This connector appears well made. How durable it is during cold weather, time will tell. After applying dielectric grease, I used two tie wraps to hold connectors together in order to keep ice/snow from pulling them apart. A longer ground wire would be nice. Using the setup for a camper. 143643



- C57674

by: Tony S.02/14/2014


Ordered this along with a receiver for my 1990 Chevy truck. Drilled two holes in my bumper for the mount . have to use your own screws for the mounting bracket to the frame the rest are supplied. Wiring instructions found on Etrailer if you need them. Great product! Thanks Etrailer! 116591



- C57674

by: Access Const.03/17/2011


2nd time purchasing from E-trailer, 1st time for this product, Pic shows 4 way attached to unit on left, does not come that way. 4 way is loose on the pig tail with a cap and slides into the meatl bracket. I see this will be a problem without securing it to the bracket better. 9584



- C57674

by: Bill B08/11/2017


The video that you have was excellent in the installation, the harness worked as described. Could have had more written instructions for the wiring for the splicing of the rear harness, if not for the video would not have known exactly what to do. But it worked well.. 419214



- C57674

by: Wpeterson07/18/2017


Customer service was awesome. I had no idea what anything was called...I'd never done this before...and they talked me through everything. The parts and directions were excellent. I really loved the install videos. ETrailer saved me money...$500 less than a dealer! 407864



- C57674

by: BLS01/21/2013


Very nice multi function adapter. The led indicator lights are very handy. Construction is of high quality. 63671


Comments

Is the indicator light supposed to always stay on even when the car is turned off? My 12v indicator lights up red all the time even when I turn the car off.

-- comment by: Blake - 01/23/2013

894

If your 12V feed is wired so that it is hot all the time, then the 12V feed LED indicator will be on all the time. These are LEDs so the amperage draw is very small.

-- Patrick B - 2/4/2013


- C57674

by: Dave P.10/20/2016


It works but the 4 pin connector is not secured in the bracket. There is nothing to keep it there. I had to use cable zip ties to mount it. If they had made the bracket wider and punched a hole for the connector, would have been the right way. 308925



- C57674

by: Michael Mower11/29/2012


This hitch electronic adapter is exactly what I needed for my Toyota FJ Cruiser which cam with a factory installed class III 2" rear hitch and the 4 pole connector. THANK YOU ETrailer staff! Merry Merry Christmas 60235



- C57674

by: Karl02/06/2017


Excellent 339253



- C57674

by: Darin07/09/2012


Well built, shipped timely, easy install. Loved the test lamps, makes it very easy to confirm the wiring is and remains setup properly. 4 way flat adapter makes switching between one trailer to another a snap. 47198



- C57674

by: shane c03/29/2017


Just got all the parts i ordered will be installing soon arrived undamaged and packaged well everything is in great shape and better quality now to install hitch and brake controller and rv plug 362691



- C57674

by: Bruce C10/07/2016


High quality product with handy test lights on the unit. Makes it possible to use a 7 pin trailer on a 4 pin vehicle for light loads. Has wiring to add trailer brake system later if needed. 304324



- C57674

by: Kelvin A.10/09/2013


I was hoping that the flat plug was mounted to the harness and not the bracket. In my case, i do not need the bracket and have to find a way to mount the flat plug in order to use it properly 103221



- C57674

by: W.C.U.06/20/2016


Easy, straight forward installation. Flawless performance. What's not to like? Money well-spent. I would never hesitate to recommend i/t to a friend or install it on another of my vehicles. 262691



- C57674

by: Matt B03/25/2016


Great product overall, exactly what i was looking for. Would have been nice if they included the hardware for the bracket that mounts to your vehicle though. Very easy to mount and plug in. 241668



- C57674

by: Norman C08/03/2014


Products works great as advertised. The resources on the web site are also a huge advantage to getting it installed. All things considered I would recommend anyone to etrailer. Thanks. 144135



- C57674

by: Jadon W01/12/2017


Install was simple and easy on my Durango. I like the lights telling me what is working or not. wish the ground wire was longer maybe 2ft. I had to splice and run extra wire to a ground. 332044



- C57674

by: BOB C.11/05/2016


STURDY, WELL MADE, FUNCTIONS AS ADVERTISED.... QUICK CONVERSION FROM THE 4 FLAT ON MY TRUCK TO A SEVEN BLADE RECEPTACLE... THE SPARE WIRES I WILL USE FOR TRAILER BRAKES AT A LATER TIME. 314078



- C57674

by: Greg R.09/17/2015


The holes didn't quite line up, but that's not a big deal. Be aware that it doesn't come with fasteners to attach the bracket to the hitch. That's ok too. This is a nice RV socket. 226164



- C57674

by: James F.06/21/2017


Simple attachment to 4 flat connector. Provides the ability to use both 4 flat and 7 round plugs, and I no longer have to worry where I put the adapter piece since I have both setups. 397355


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Ask the Experts about this Curt Wiring
Do you have a question about this Wiring?


  • How to Install a 7-Way Trailer Connector to Add a 12 Volt Power Lead to a Trailer
  • It sounds like you are missing a wire for the running lights on your trailer. Trailers that are wired for lights will have 4 or 5 wires, one for right stop/turn, one for left stop/turn, one for ground and one, possibly two, for running lights. Does your trailer have functioning turn signals, brake lights and running lights? If the two brown wires you mentioned are separate wires from the green and brown and yellow and brown wires, then you have a wishbone harness, which means you have a...
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  • Wiring Diagram for the Curt 4 Pole to 7 Pole Adapter # C57674 And Wiring for Trailer Brakes
  • The wiring for the Adapter 4 Pole to 7 Pole and 4 Pole, item # C57674, is wired as follows. The white wire is grounded to the vehicle frame as you have indicated. The Yellow wire is the center pole of the 7-Way connector and is normally used for connection to the reverse light circuit. In your case you will not need the yellow wire. The blue wire is for connection of the electric brake feed wire from a brake controller. You will need a brake controller in your Sienna to activate the...
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  • What do the Codes for the Test Lamps Mean on CURT Adapter 4 Pole to 7 Pole and 4 Pole # C57674
  • On the CURT Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps, # C57674, the test light codes are as follows: 12V = 12 volt hot lead BK = output from brake controller (if no brake controller is installed, this light will not light up) BU = reverse lights (if this circuit is not connected on the vehicle it will not light up) RT = Right Turn TM = running lights (tail/marker lights) LT = left turn
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  • Adding 7-Way Trailer Connector to 2014 Toyota Tacoma without Factory Tow Package
  • It sounds like your 2014 Toyota Tacoma did not come with a factory tow package. What can happen sometimes is that on models that did not come with the factory tow package not all of the wiring or contacts will be present. You would either need to by all of the tow package parts or you would need to return the harness and install an aftermarket one designed for models without the factory tow package. If you want to add a 7-Way to the truck you would start by installing a 4-Way using #...
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  • Adding a 7-Way and Brake Controller to a 2015 Ford Expedition with Factory 4-Way
  • From what we have found the 2015 Ford Expedition that came with a factory 4-Way connector will need a little bit of hardwiring to install a brake controller and 7-Way connector. You will need # 37185, some wire (more on that later), a brake controller, and a brake controller wiring harness. The 37185 will plug into the 4-Way. Then you will ground the white wire to the frame. That will leave a blue wire, black wire, and purple wire. The purple wire is for reverse lights so if the trailer...
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  • Trailer Brake Controller Installation on a 2014 Toyota Tacoma Pre Runner Without Tow Package
  • I checked your recent order and I see the components you already have: Curt 4-Pole to 7-Pole Adapter # C57674 and Tow Ready T-One Vehicle Wiring Harness # 118496. Since you have an under-dash brake control port you can use a plug-and-play harness to connect a brake controller such as the Prodigy P2, part # 90885, which is one of the most popular and reliable proportional brake controllers we offer. First I suggest you test the under-dash port to ensure it is active. The presence of wiring...
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  • Parts Needed to Install a 7-Way Trailer Connector on a 2006 Toyota Tundra with 4-Way Connector
  • I see you already purchased the Curt 4 Pole to 7 Pole Adapter, # C57674. This is the appropriate adapter to convert your 4-way trailer connector to a 7-way trailer connector. Since you do not have any turn signals or brake lights, I recommend testing your original 4-way trailer connector with a circuit tester like part # 40376 for those functions first. I have attached a demonstration video showing how to use a circuit tester to test a 4-way trailer connector for you to check out. I also...
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  • Turn Signals and Running Lights Not Working with T-One Wiring Harness and 7 Pole Adapter Installed
  • The first step that I would take to troubleshoot this issue is to sever the 12 volt power wire from the Curt 7 Way Adapter, # C57674, from the power wire of the Tow Ready 4 Way Wiring Harness # 118552. The 12 volt power wire from the Curt 7 way adapter should run directly to the vehicle battery via a 40 amp inline circuit breaker, # 9510. If you do not want to have to run another power wire to the vehicle battery, then you will want to install the 10 amp inline fuse from the 4-way harness...
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  • Do I Need To Install A Brake Controller To Activate Or Deactivate Surge Trailer Brakes In Reverse?
  • Great question. Let me cover brake activation first. If you wish to have active braking on a hydraulic system when backing up, you would need to have Electric over Hydraulic brakes and not a surge brake coupler. Surge brake couplers do not allow active braking when in reverse. To add the electric over hydraulic system, it will require a brake controller like # 39523 and an electric over hydraulic brake actuator like the HydraStar Vented Marine Electric Over Hydraulic Actuator for Disc...
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  • All Lights Work Except Brake Lights on Trailer Towed by 2013 Kenworth Class 8 Truck
  • Class 8 trucks typically have a different set up 7-Way than passenger vehicles and that could be the issue. Disconnect the trailer from the tow vehicle and use a circuit tester, such as # 3808, to test the pins on the vehicle side connector. Have someone sit in the truck and step on the brake while you test the pins in the 3 oclock and 9 oclock positions. If the brake pedal does not make the tester light up then this is most likely the issue. Trailers that take a 7-Way blade style connector...
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  • 7-Way Connector and Brake Controller Recommendation for a 1998 Chevy Cheyenne K1500 4x4
  • If you install a Curt Wiring Adapter # C57674 onto your 1998 Chevy Cheyenne, you could use either the 7-Way or the 4-way adapter to hook up to your trailer. If you do not have one, you will first need a 4-Way connector at the rear of your truck. I would recommend you get a Tow Ready T-One Vehicle Wiring Harness, part # 118315. I attached installation instructions for this product below. If you used the 7-Way, it would function just like a 4-Way in that you would not have trailer...
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  • 7-Way Trailer Connector for 2011 Toyota Highlander
  • If all you are needing to do is provide lighting functions for the camper (directionals, running lights and brake lights) and if your Highlander already has a 4-pole trailer connector, you will only need a 4-pole to 7-way Adapter, part # 37185. If you do not already have the 4-pole connector, you will additionally need the T-1 Connector, part # 118449. If your camper has electric brakes, you will need a brake controller. I would recommend the Tekonsha Prodigy P2, part # 90885. The...
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  • Installation Instructions for 4-Pole to 7-way Adapter Part # C57674 for 2003 Dodge Ram
  • The 4-pole connector attaches to the existing 4-pole on your vehicle, which leaves the four loose wires. The white wire with the ring terminal would ground to clean metal. The blue wire carries the output from the brake controller. Since your truck was not equipped with the 7-way connector, the brake controller output wire ends in the front wheel well of the truck, and would need to be extended back to the trailer connector (see photo). The black wire carries 12-volt power for any trailer...
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  • Installing a 7-Way Trailer Connector on a 2017 Subaru Outback Wagon
  • That is correct for your 2017 Subaru Outback we only carry 4-way trailer connectors that are a direct fit. However, once you install the 4-way it can be converted to a 7-way, if that's what your trailer needs. Of the 4-way connectors for your Outback I recommend the Tekonsha # 118467 because we always have great success with them. To install the harness you'll need to locate the factory connector in the Subaru's rear cargo area. Then install the included fuse. I've linked an install...
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  • Indicator Lights on Curt 4-Pole to 7-Way Adapter
  • When fully installed, all the lamps would be lit as each function was activated. The BK or brake would not be lit, as you do not have a brake controller installed. The BU lamp would only light if the vehicle transmission were in reverse and that yellow wire was tapped into the circuit feeding the reverse lights on the vehicle. The 12V lamp would only light if the black wire was attached to the positive battery terminal. The 12-Volt circuit should be circuit protected using a 40 amp inline...
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  • How to Wire Up a Curt Brake Controller on a 2011 Chevy Silverado
  • For a color to color application you will run the black wire from the brake controller to the red/black wire from your truck, the white wire from the controller to the white wire of your truck, the red wire from the controller to the light blue/white wire from your truck, the blue wire from your controller to the dark blue controller of your truck. I attached a picture of a chart to make this easier also. I also attached a video of a brake controller being installed on a similar 2011...
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  • Should the 12V Lamp Always be Lit Even when the Car is not Running and the Keys are Out
  • The 12 volt power wire from your 7-way connector will always be hot if it was attached to the positive terminal of the vehicles battery, even with a 40-amp circuit breaker installed. To prevent your trailer from constantly drawing power from your vehicles battery, I recommend installing the Tow Ready Battery Isolation Solenoid, # TR118665, inline on the power wire. This will prevent your vehicle battery from draining when a trailer is connected. I have attached a photo that shows how the...
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  • TM Light Stays Lit On Curt Adapter 4 Pole To 7 Pole And 4 Pole With Test Lamps
  • I spoke with my contact at Curt about the Adapter 4 Pole to 7 Pole and 4 Pole w/Test Lamps, part # C57674. They told me that if the vehicle has running lights as so many later model vehicles do, the TM test light will show there is current by lighting up. it sounds as though it is working just fine for you.
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  • Available Wiring Adapters to Provide Both 7-Way and 4-Pole Connectors
  • Hopkins 7- and 4-Pole Trailer Connector Socket # HM40975 is a replacement trailer connector that has both 4-pole flat and 7-way blade style connectors. It installs on a round U.S. Car Connector type plug. This is not an adapter that converts one wiring format to another. If you want an adapter that plugs in to a 4-pole and provides both 4-pole and 7-way connectivity then you can use part # 37185 or # C57674. This will plug in to your 4-pole wiring and provide those lighting signals in...
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  • Troubleshooting Trailer Connectors That Do Not Pass Running Lights or Turn Signals
  • The best way to troubleshoot trailer wiring is to first test your Acadia's 4-pole WITHOUT the Curt adapter. This will let you know if the signals are reaching the adapter. Even though the LED test lights may come on, since these take so little power to light up it could be that there is a small residual voltage in the system that is causing them to illuminate even when no actual running light or turn signal is reaching the adapter. You can use a tester like the # 40376 to check the Acadia's...
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  • How to Install Auxiliary 12 Volt Battery Charge Circuit on a 2007 Toyota Highlander Hybrid
  • Yes, you can use the 12 volt battery in your 2008 Toyota Highlander Hybrid to help maintain the charge on your camper battery when the vehicle is running. Vehicle charging systems do not provide enough output to charge a trailer mounted battery from a discharged state, even if they are not Hybrid vehicles, so you will need to bring your trailer battery up to full charge with a battery charger before leaving on a trip. You could wire a charge circuit to the adapter you chose, # C57674....
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  • Troubleshooting Left Turn Signal Staying Hot on a 2013 GMC 3500HD Towing a Trailer
  • If you used a 7-way circuit tester like our 7 Way Trailer Connector Vehicle Tester # TR20117 and the LT circuit stayed lit that would indicate that there is voltage on this circuit at all times which means something is shorting out onto this circuit. Due to the fact that it is hot all the time it would seem that it is the 12 volt power circuit that is shorting to the left turn/brake circuit. I suspect you have a 7-way round connector since on these style connector the left turn and 12...
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  • Installing 4 Pole to 7 Pole and 4 Pole Adapter # C57674 on a 2010 Toyota FJ Cruiser
  • Installing an aftermarket part, like the Adapter 4 Pole to 7 Pole and 4 Pole, # C57674, will not void the warranty on your 2010 Toyota FJ Cruiser unless it is the direct cause of a problem. There is actually a law you can look into called the Federal Magnusson-Moss Warranty Act. The Act states that if something breaks on your vehicle and you take it in for warranty repair, the dealer must honor your warranty unless the modification actually caused the problem in question. I do not have...
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  • BK LED on Curt 7-Way Adapter, Part # C57674, Remains Lit Even Without a Trailer Connected
  • If you do not have a proportional brake controller (but instead have a time-delay type) the LED being lit could indicate a short to the controller output circuit. In some cases the manual brake switch on your controller may be partly engaged; this would also cause a signal to be sent to the 7-way BK LED. You can correct this by flipping the manual switch on and off several times to clean the contacts. If you are using a proportional type brake controller such as the Prodigy P2, part...
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  • Brake Controller 7 and 4 Way Installation Kit without the Pre-wired 7 and 4 way Trailer Connector
  • What you can do to complete the installation of the CURT 7-Way and install a Tekonsha P3, # 90195, is to use the Wiring Kit # 5506. You would also need one 40 amp circuit breaker for the 12 volt hot lead, # PK54540. You would still follow the FAQ and video for the # ETBC7 which I have linked for you. The Adapter 4 Pole to 7 Pole, # C57674, should have come with a mounting bracket and self-tapping screws so that you could mount it to a flat surface (not the hitch) under the vehicle. Something...
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  • LED Indicator Light on Curt Trailer Wiring Harness Is On All the Time On 2013 Dodge Grand Caravan
  • The Curt trailer wiring harness for the 2013 Dodge Grand Caravan is # C56331. I could not find information on a 56187. The correct harness does not have an LED indicator light on it anywhere. There are some adapters, like # C57674, that have LED indicators to tell you a circuit is working on or not. In this situation the 12 volt indicator light will always be on because the 12 volt circuit is hardwired directly to the battery. In order to not have it come on it would have to be wired...
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  • Will Indicator Light of Curt 7-Way with Tester Drain Vehicle Battery
  • The LED indicator lights of the part # C57674 would not draw enough amperage to kill your vehicle battery. It would take months of inactivity for it's amperage draw to make a difference and and that point the battery would have drained from inactivity.
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Info for this part was:

Test Fit:
Joe V
Photos by:
Theodore B
Expert Research:
Michael L
Video Edited:
Zack K
Expert Research:
Robert G
Expert Research:
Michael H
Expert Research:
Jeff D
Expert Research:
Jameson C
Video Edited:
Joshua S
Test Fit:
Nicholas E
Video Edited:
Jacob T
Expert Research:
John H
Updated by:
Adele M
Expert Research:
Adam R
Expert Research:
Rachael H
Expert Research:
Jeffrey L
Video by:
Alan C
Video Edited:
Chris R
Updated by:
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Test Fit:
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