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Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End

Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End

Item # C57187
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Convert your vehicle's 4-way flat trailer connector to a 5-way flat. Plug the 4-pole connector into your vehicle and connect the wire leads to get the electric brake function. Lowest Prices for the best wiring from Curt. Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End part number C57187 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (23)
  • Q & A (41)
  • Videos (2)
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  • Why etrailer?

Curt Wiring - C57187

  • Wiring Adapters
  • Single-Function Adapter
  • 5 Flat
  • Plug and Lead
  • Curt
  • 4 Flat

Convert your vehicle's 4-way flat trailer connector to a 5-way flat. Plug the 4-pole connector into your vehicle and connect the wire leads to get the electric brake function.


Features:

  • Adapter converts your 4-way flat trailer connector to a 5-way flat trailer connector
  • Additional wire leads for reverse lights
  • Durable molded plastic construction resists corrosion
  • Simple installation
    • Wiring harness plugs into existing 4-way flat connector and hardwires to existing wiring


Specs:

  • Wire configuration:
    • Green: right turn signal and brakes
    • Yellow: left turn signal and brakes
    • Brown: tail lights
    • Blue wire: reverse lights
    • White wire: ground wire
  • 1-Year limited warranty


57187 Curt Trailer Connector Adapter - 4 Way Flat to 5 Way Flat




California residents: click here


Video of Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End

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




Video Transcript for Curt Wiring - Wiring Adapters - C57187 Review

Speaker 1: Today we're taking a look at a Curt trailer connector adapter four-way flat to five-way flat for the vehicle end. This adapter converts your four-way flat trailer connector on your vehicle to a five-way flat trailer connector to work with your trailer wiring. It does come with additional wire leads for electric brakes. The connectors are molded. It's a durable molded plastic construction, which is designed to last a long time and resist corrosion. Pretty simple installation.

The harness plugs into your existing four-way flat connector at the back of your vehicle and it hard wires to the existing wiring for the electric brake function. And then this right here is your five-way flat, which would connect to the five-way flat on your trailer.This wire right here has the pre-attached connectors on it, so this is the one that would hard wire to the vehicle. You've got the bare end on this side, then you have the connector right here, which mates up perfectly with the connection point on the wire that comes from the five-way flat. It's always a good idea to go ahead and wrap that up, maybe in some electrical tape or put a heat shrink outer wrap on that to seal it up, keep the elements out. This piece right here measures 36 inches.

This piece right here measures 26 inches. And the wiring between our two connectors measures two and 1/4 inches.That's gonna do it for today's look at the Curt trailer connector adapter four-way flat to five-way flat.


Customer Reviews

Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End - C57187

Average Customer Rating:  4.7 out of 5 stars   (23 Customer Reviews)

Convert your vehicle's 4-way flat trailer connector to a 5-way flat. Plug the 4-pole connector into your vehicle and connect the wire leads to get the electric brake function.

- C57187
by:

It was easy to determine what product that I needed because of the video associated with the produce. My order came quickly and was the exact one I ordered. 661395



- C57187
by:

I cannot give this item a fair rating as the trailer lights on my 2016 trailer do not work. The trailer is in absolute MINT condition so no problem there. I had the wiring checked on my 2011 Toyota Siena, everything there checked out A-OKAY, but when I attached the adapter to my Van/Trailer wiring, nothing, no lights. I talked with a gentleman from etrailer but he was of no help and not able to offer a possible solution. The wiring harness was installed on my Toyota three years ago for a different trailer that took a 4-way flat to a 4-way flat and worked flawlessly with that trailer. 508250


Comments
Anytime theres a trailer wiring issue, the first step is to narrow down where the problem actually is. Use a circuit tester like # 40376 or a multimeter to test each pin on the trailer connector as a helper applies the brakes, uses the turn signals and turns on the headlights. This will confirm the functionality of the wiring harness on the vehicle. Next, plug in the # C51787 adapter. Test each pin on the adapter as its function is activated. If all checks out okay, youve ruled out the vehicle and the adapter as being the problem, which leaves the trailer. Weve seen wiring problems on brand-new trailers, so its entirely possible that the problem could exist on the trailer, regardless of its overall condition and appearance. To test the trailer lights independently of the tow vehicle, you an use a 12 volt battery. Ground the battery to the trailer frame, then apply power from the positive battery post to each pin on the connector and see if the lights for each circuit illuminate. Ill also link you to some Help articles about trailer wiring. One article will help you understand the basics of how a trailer wiring system works, the other helps with basic troubleshooting. https:www.etrailer.com/faq-wiring.aspx
-- Mike L - 05/15/2018

38526

- C57187
by:

Works as expected 846219



- C57187
by:

Awesome 809905



- C57187
by:

Solid product. Worked as advertised and very easy installation. And Will Call worked great...ordered and picked up in the same day:) 807827



- C57187
by:

Products were exactly as described and work great. Had all the accessories I needed and showed up on time. Also came with detailed instructions on how to install! Will.use them again. 795641



- C57187
by:

I got it yesterday! Couldn't be happier with the turn around time. Thank you 794188



- C57187
by:

Excellent product. Exactly what I needed to hook up my five pole trailer to my four pole truck. 793893



- C57187
by:

Did and does exactly what is is designed to do. 710528



- C57187
by:

Exactly what I ordered! Fast shippin g. 704699



- C57187
by:

Just what I needed to get my surge brakes from engaging on uphill backups! The video for my 2019 Highlander helped immensly. Toughest part was wiring tot he reverse light circuit but once that's done no more surge brake "backup" headaches. 691231



- C57187
by:

Perfect part and quick shipping! 690700



- C57187
by:

It came quickly and was exactly what I needed for a great price. 687056



- C57187
by:

etrailer folks are terrific. When ever I call they have a solution for the situation at hand. In this case I needed an electrical connector to adapt my boat trailer to a new vehicle and Robert knew exactly the correct product to use. Courteous friendly help as usual. 666756



- C57187
by:

Excellent product 662976



- C57187
by:

Installed on a 2017 Jeep Wrangler unlimited. Product arrived as stated. Easy to install took abou 10 minutes. I have pulled my boat several times lights work and the main reason was to dis-engage the surge brake when in reverse. Works great!! 650400



- C57187
by:

Quick install, highly recommend the ada pter. 628248



- C57187
by:

Works 599458



- C57187
by:

YOU GUYS ARE THE BEST..............Easy to deal with and reliable! Thanks! 574353



- C57187
by:

Second item that I ordered from etrailer.I was able to easily track it and it arrived quickly. Perfect fit from my new truck to my boat trailer. Thanks for the excellent service! 571734



- C57187
by:

great !!! 563852


Comments
Still working perfectly!!
Bryan - 09/11/2019

61028

- C57187
by:

Ordered Monday night and here Thursday before I needed it! No auto part stores in my area had what I was looking for but these guys sure did. Thanks! 549334



- C57187
by:

Product as specified on eTrailer site to solve a particular problem between my car and a boat trailer. Excellent description and instructions. 509831


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Ask the Experts about this Curt Wiring

  • 4-Way to 5-Way Adapter for 2019 Toyota Highlander Towing Boat Trailer
    To convert the 4-way of your 2019 Toyota Highlander to a 5-way requires the 4-way to 5-way adapter part # C57187. This plugs into the 4-way you have now and then gives you an additional wire you'd run to the reverse light circuit of your vehicle. To prevent wires from being visible would require you to route the wire behind interior panels on it's way to the reverse light wiring.
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  • Recommended 5-Way Adapter for Vehicle 4-Way Trailer Connector Wiring Harness to Work With Trailer
    For your trailer with 5-way flat connector to connect to your vehicle 4-way flat, I recommend the Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End # C57187 or the Tow Ready # 20036. The blue wire will connect to your reverse light wire at your tail light utilizing the quick connect supplied with this adapter.
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  • How to Wire 5-Pole Trailer Connector on Hitch Cargo Carrier to Match 5-Pole Vehicle Wiring
    4-pole flat and 5-pole flat trailer wiring harnesses actually use the same function-to-pin configuration for the three basic lighting circuits they have in common. These three are left stop/turn, right stop/turn and running light circuits. If a 4-pole and a 5-pole can be physically connected together, meaning if their plug shapes fit together without interference from the molded plastic housings, they'll work together just fine without need for an adapter. On some plugs it may be necessary...
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  • How To Activate Surge Brake Reverse Solenoid On Vehicle with 4-Way Harness
    In order to activate the reverse solenoid on the brake actuator you will need to converter the 4-way trailer wiring harness you have to a 5-way using the Curt Trailer Connector Adapter part # C57187. This adapter will then plug into the 4-way on the vehicle and allow you to hook-up the 5-way on your trailer but you will need to run one wire from the adapter to the reverse light circuit on your vehicle. In order to find the correct reverse light circuit on your vehicle you will need to obtain...
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  • How to Install a 5-Way Trailer Connector on a 2003 BMW X5
    Yes, we have exactly what you need. For this, you are going to want to use the Curt Trailer Connector Adapter part # C57187. This adapter is going to plug into the 4-way on your X5 and then the blue wire will splice into the reverse light circuit. This will then allow the brakes to release on your trailer while in reverse. They do not make a 5-way wiring harness specially for your X5 so this is going to be your best option.
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  • Solution to Allow Motorcycle with 5-Way to Tow Trailer with 4-Way
    Typically if the trailer was designed to be towed by a motorcycle it would use the motorcycle standard 5-way connector that has the correct wiring setup as well. But I can help you come up with a wiring adapter either way. On the motorcycle you'll need to wire in the adapter # RM-732 and you'll be set. This will convert the separate style of wiring your motorcycle has to the combined of your trailer. The extra pin that uses to carry just the brake signal will not be used on the motorcycle's...
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  • How to Attach a Motorcycle Trailer with 5-Way to Vehicle with 4-Way
    If your motorcycle trailer has a 5-way flat then you will need to use the Curt Trailer Connector Adapter part # C57187 in order to attach it to your tow vehicle. However, if your motorcycle trailer has a 5-way round then you will need to remove this and install a 5-way flat, the Hopkins Wiring Harness with 5-Pole Flat Trailer Connector part # HM37918 as there are no adapters to go from a 5-way round to a 4-way flat. If none of the trailer lights work once you have the correct adapter...
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  • Adding 5-Way for Trailer with 4-Way for Adding Reverse Lights
    Basically you are going to have to remove the 4-way you have and replace it with a 5-way like the part # HM47910. You'll wire this to 4-way wiring color for color and then the 5th pin for reverse lights would need to be ran back to the reverse lights on the trailer. So the new wiring you put on the trailer would not be affected and it would mainly just be you swapping the connectors and running just additional wire.
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  • How To Install 5-Way Trailer Connector On 2012 Nissan Pathfinder with 4-Way
    The only option to install a 5-way trailer connector on a 2012 Nissan Pathfinder is with an adapter, the Curt Trailer Connector Adapter part # C57187. In order to mount this you'll need the Mounting Bracket for Wesbar 5-Pole Flat part # tr20046. There are unfortunately no plug-in-play options to install a 5-way trailer connector. In regards to installation, you'd simply need to find the reverse light wire behind the tail lights but we don't have any videos of this.
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  • Replacement for Atwood 61101 Brake Actuator
    The Demco Hydraulic Trailer Brake Actuator part # 8605001 should be a direct replacement for the Atwood 61101 Brake Actuator that you have now. This is a bolt on option that mounts on 3" centers. The review you are referring to, the customer did indeed weld the brake actuator to his tongue but this is not required for installation because it is a bolt-on actuator. Unfortunately, we do no offer a bolt-on brake actuator for drum brakes with a manual lockout that will work for you therefore...
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    For surge brake actuators, the solenoid like the Replacement Solenoid Valve for Titan Brake Actuators with Reverse Lockouts # T4748800 will allow you to bypass your brake actuator when backing up. The unit screws into the back of your master cylinder and then the brake line connects to the other end. One wire of this electric lockout solenoid will connect to the trailer frame as a ground and the other will connect to the reverse light function wire coming from your vehicle. You can connect...
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  • Will the Titan Brake Actuator T4749600 Allow for Reversing Uphill
    The Titan Brake Actuator part # T4749600 does not come with a lockout so in order to reverse you'll need to install a lockout solenoid, the Replacement Solenoid Valve for Titan Brake Actuators with Reverse Lockouts part # T4748800. This would also require a 5-way trailer connector so you'll also need the Curt Trailer Connector Adapter part # C57187 and Hopkins Wiring Harness part # HM37918. That said, in regards to uphill reversing you'll need to do so very slowly as left over fluid...
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  • What Causes a Trailer With Surge Brakes To Lockup While In Reverse
    The issue your friend is having with his trailer is a mechanical one so we can rule the vehicle out. The reasoning for this is because the only way you would have been able to back up the trailer with using just a 4-way trailer connector is if you either physically applied a manual lockout or the trailer had free backing braking assemblies. Surely you would know whether or not the manual lockout was used or not so that leads me to think you have free backing braking assemblies. The free...
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  • Parts Needed To Rewire Trailer Using 5-Way for Reverse Circuit
    I have just what you need to rewire a trailer using lights with a built-in reverse function. For this, I recommend a standard 5-way trailer connector which will provide circuits for stop, turn, tail, and reverse. The 5-Way Trailer Wiring Harness part # A40W5B is what I recommend for this as it has enough wire to completely redo the trailer lights with all new wires. I also recommend the Deka Heat Shrink Butt Connectors part # DW05744-10 and CE Smith Trailer Wiring Clips part # CE16867A...
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    I think I understand what you are asking. For your 2015 Jeep Cherokee, the T-One Vehicle Wiring Harness with 4-Pole Flat Trailer Connector # 118605 will give you the basic trailer functions as you stated and then you can add the reverse feature alone using the Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End # C57187 and simply use the quick splice to tap into the reverse light at your tail light on either side. This will give you a 5-way flat connector that is...
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  • Part Needed to Convert 4-Pole Wiring Harness to 5-Pole Flat Connector Format
    We do not have 5-pole type wiring harnesses for your 2012 Chevrolet Traverse but it is easy enough to adapt 4-pole wiring to the 5-pole format simply by adding an adapter kit. We offer three such items, parts # 20036, # 47515 or # C57187. I linked an install video for part # 20036. All of these include an additional wire/circuit to allow connection to the reverse light circuit for a trailer coupler lockout function or for any other circuit function you require.
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  • How To Install a 5-Way Trailer Wiring Harness on a 2019 Honda Pilot for a Boat Trailer
    They do not offer a direct plug and play 5-way trailer wiring harness for your 2019 Honda Pilot or most vehicles for that matter nowadays. The only way to obtain a 5-way trailer wiring harness is to use a 4-way trailer wiring harness, the Curt T-Connector Vehicle Wiring Harness part # C56291 and then a 4 to 5-way adapter, the Curt Trailer Connector Adapter part # C57187 which only requires one splice on the vehicle and trailer. The reverse light circuit on your Pilot should a brown wire...
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  • How To Attach Trailer with Six Way Using Vehicle with Four Way
    In order to reverse a trailer with surge brakes you most likely need a lockout feature. The most common type of lockout feature is electric which would seem to be what you have due to the type of trailer connector installed. I do have an option for you but the four pin trailer connector on the vehicle does not contain a reverse circuit which is needed for the electric lockout. I have attached a few options below. Option 1: The first option would be to remove the six way on the boat...
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  • How to Disengage Brakes on a Boat Trailer While in Reverse
    If the brake actuator on your boat trailer has an electric reverse lockout solenoid like part # T4748800 and you were using the 7-way side of the 7- and 4-Pole Trailer Connector Socket part # HM40975 then yes, the brakes would release while in reverse. However, in order to use this harness on your vehicle you will need to have a U.S. car connector plug like part # C56229 already installed. If not then you can use something like part # C57187 to release the brakes on the trailer while in...
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  • How To Wire a 4-Way On a Motorcycle Trailer With a 6-Way
    It sounds like you have a 6-way trailer connector on your motorcycle trailer and you want to replace it with a 4-way trailer connector. If that is the case then I do have options for you but I would need to know exactly what powered circuits you have on your trailer. If you were to use a 4-way trailer connector like the one you have pictured then you could only retain left stop/turn lights, right stop/turn lights, and running lights. In order to wire the new 4-way onto the trailer you...
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  • Parts Needed to Tow Trailer with 2015 Volvo XC60
    For your 2015 Volvo XC60 I recommend going with the Curt # 13268 hitch because the heavy powder coating that Curt uses on their hitches is going to help protect against rust and corrosion, which will be especially helpful in the wet Florida climate. This will be a great choice for your Volvo XC60 and will provide you with a safe solution for towing your boat. In order to tow a trailer you'll also need a few other things: a wiring harness, ball mount and hitch ball. For a wiring harness...
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  • How To Install a 4-Way Trailer Connector on a 2016 Buick Enclave
    If you have a 2016 Buick Enclave then there should be a tow plug that will allow you to connect a 4-way trailer connector without having to tie in behind the taillights or splice into any wires. This plug should be present whether or not you have the factory tow package however, if you don't have the factory tow package then you will need to install the fuses and relays that come with the kit. I recommend the Curt T-Connector Vehicle Wiring Harness part # C56245. If you take a look at...
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  • Trailer Wiring Recommendation for 2016 Ford Explorer with Reverse Light Circuit
    Easiest solution would be to replace the 4-way part # 118540 that you have installed on your 2016 Ford Explorer with the 7-way part # 118272 which uses the same install point at the rear of your vehicle. The reverse light circuit will be present here on the center pin. To convert the 7-way to a 5-way you'd then want the # A75TB. Or the other option you have would to keep your 4-way and then install a 5-way adapter to it. For that you would want part # C57187. The issue here is that...
    view full answer...
  • How To Add a 5-Way Flat Trailer Connector To a 2017 Toyota Highlander with Tow Package
    In order to add a 5-way flat trailer connector to a 2017 Toyota Highlander you'll need to start with the Curt T-Connector Vehicle Wiring Harness part # 56042 which is plug and play and has a 4-way flat connector. Then, you can add the Curt Trailer Connector Adapter part # C57187 to convert the 4-way to a 5-way. The blue wire gets spliced into the vehicle's reverse light circuit. Unfortunately, they don't offer a one piece 5-way flat trailer connector for most vehicles so you must use...
    view full answer...
  • Adapter To Convert 4 Flat To 5 Flat On A 2011 Nissan Pathfinder
    The Curt Trailer Connector Adapter - 4-Way Flat to 5-Way Flat - Vehicle End # C57187 is what you are looking for in this situation. Included are a couple of video resources providing an overview as well as an installation walk through to help you get started. Basically you will plug into the existing 4-Way on your Pathfinder. The blue wire then gets spliced into the reverse circuit wire on the vehicle for the reverse lockout on the boat trailer.
    view full answer...
  • How to Use the Lockout on the Titan Brake Actuator with Manual Lockout Part # T4500600
    In order to engage the reverse lockout on the Titan Brake Actuator with Manual Lockout part # T4500600 you will need to insert the lockout tool which should be included, into the channel directly behind the coupler. I have pointed this channel out for you as well as the tool that is needed. If you don't have this tool then you will need to obtain this from the manufacturer. However, the other option you have is to add an electric lockout that will work when you place the tow vehicle...
    view full answer...

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Info for this part was:

Edited by:
Lindsey S
Expert Research:
Jameson C
Expert Research:
Adam R
Video Edited:
Jacob T
Video by:
Dustin K
Installed by:
Cole B
Written by:
Amanda M
Test Fit:
David F
Updated by:
Kristina F
Updated by:
Isabelle B

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