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Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat

Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat

Item # C57102
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C57102 - Plug Only Curt Wiring
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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 an integrated backup alarm. Lowest Prices for the best wiring from Curt. Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat part number C57102 can be ordered online at etrailer.com or call 800-298-8924 for expert service.
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  • Reviews (17)
  • Q & A (19)
  • Videos (1)
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  • Why etrailer?

Curt Wiring - C57102

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

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 an integrated backup alarm.


  • Connects to 4-way flat plug on your vehicle
    • Requires additional wiring for use of brake, power and accessory leads
  • Supplies 7-blade RV and 4-wire flat trailer connections
  • Sounds alarm when vehicle is in reverse
  • Constructed of durable plastic


  • Yellow wire is for reverse lights
  • Blue wire is for brakes
  • Black wire is for 12 volt power
  • White wire is ground
  • 4-Way connector plugs into vehicle 4-way connector

57102 Curt Multi-Function Socket with Back Up Alarm - 7-Way RV Blade and 4-Way Flat - Universal Fit

Installation Details C57102 Installation instructions

California residents: click here

Video of Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat

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

Video Transcript for Curt Wiring - Wiring Adapters - C57102 Review

Man: Today we're going to be taking a look at Part Number C57102. This is a Curt Trailer Connector Adapter with a backup alarm. This is 4-way, the 7-way round and 4-way flat. The multi-function vehicle end connector is going to convert any 4-way flat connector vehicle end plug to a combination of a 7-way outlet which is going to be this portion right here. And a 4-pole flat outlet. It's also going to feature the integrated backup alarm and it's going to have three LED lights on there as well. This is designed to connect to a 4-way flat plug on your vehicle.

You're going to have the connection right here to make that appropriate connection. It is going to require additional wiring for the use of brake, power, and accessory leads. All of the brake or . excuse me. All the wires here included in the harness or the adapter are going to have the appropriate connectors on here.

You're going to have three of them that are going to have the butt connectors and then the white is going to be your ground and that's going to have the ring terminal on there that will need be attached with a self-tapping screw. So again this is going to supply your 7-blade RV connector right here as well as a 4-way flat trailer connector. It's going to have the nice dust cap that goes over the connection points to prevent them from any type of corrosion. And then on the 7-way connector it's got the nice spring loaded lid that's going to protect the connection points as well. Now this is going to be constructed of a durable plastic construction. It's going to come with a mounting bracket and the necessary hardware to mount the connector to the actual bracket. You will need the hardware to mount the bracket to the vehicle, that is going to be sold separately.

Through these holes right here that's going to connect using two number 10 half inch self-tapping screws. You can also use a number 10 half inch self-tapping screw to mount the ground connection with the ring terminal here on the end of the white wire. Now to go over the wire functions real fast with you, the yellow wire is going to be for the reverse lights. Your blue wire is going to be for the brakes. The black wire is going to be for 12 volt power and then your white wire is going to be for your ground connection and then you're going to have the four way connector that's going to plug into the existing vehicle 4-way connector. Once you have all those connections made, you're going to have full use of your 7-way connector right here as well as the 4-way flat connector right here. I'm going to show you how it mounts with the bracket.

Just run all the wiring through the slots there, feed your 4-way flat through there as well. Now the holes in the bracket are going to line up perfectly with the holes here on national connector. Now that's going to be able to mount to the rear of your vehicle. It's going to hold it place and you have a little area here on the side of the bracket for your 4-way connector as well so it's going to stay right there next to the 7-way connector. That bracket is going to hold it in place. So real quick I just want to go ahead and show you the function here of the backup alarm. I'm going to go on and make our necessary connections and then you can see how that operates. Sends out a nice strong signal. It's really loud. You'll be able to see the lights flash as well. I'm going to activate the reverse function (beeping sound). That's going to sound and flash anytime the reverse function is activated on your vehicle. That's going to do it for today's review of Part Number C57102. This is the Curt Trailer Connector Adapter with the built in backup alarm. .

Customer Reviews

Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat - C57102

Average Customer Rating:  4.8 out of 5 stars   (17 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. Features an integrated backup alarm.

- C57102

Not an Easy hookup for my new Rubicon as stated. 596427

- C57102

Just what I needed, easy to install. Excellent instructions. Good quality at a good price. etrailer, my go to place for everything "trailer/towing", Not my first purchase. Don't spend too much time shopping around, you'll be frustrated with the wasted time. Thanks 122738

- C57102
by: 12/29/2020


- C57102

Love it 851126

- C57102

Product exactly as described. Shipped fast and in good condition. 764985

- C57102

Great product for the price not to mention hella easy hook up thanks holly recommended 737910

- C57102

It fit perfect, and we pulled our camper to California from Ohio and back, no problems. 680858

- C57102

I like what I see but unable to give an accurate review because I don't have it installed on my vehicle yet since I just got it this afternoon and had other projects in the process at the moment. 678966

- C57102

Great product....easy wiring and mounting...works flawlessly 662469

- C57102

very well built, easy to install. made converting from 4 wire flat connector to 7 wire round an easy process. I will use the 12 volt battery and the backup wire ,don't need the brake wire. 596360

- C57102

great product at a good price shipped f ast 595053

- C57102

My son got it on and works great. Fast service. Can not complain. 556152

- C57102

LOVE/LOVE/LOVE "this" particular model= it has a "beep" warning alarm noise system when you are backing up! IT ALERTS! YOU-LOUD! AWESOME/much needed upgrade from what came with my vehicle. 492252


Great product and quickly received 421602

- C57102

Great high quality at a very reasonable price . 342672

- C57102

Good product and install instructions. The only complaint is the 4 pin connector falls out of the housing. 240734

- C57102

Very good quality and super fast shippi ng 133138


Ask the Experts about this Curt Wiring

  • Parts Needed to Add 7-Way and Brake Controller on 2017 Subaru Outback Wagon
    In order to install a fully functional 4- and 7-Way connector on your 2017 Subaru Outback Wagon you will need to start with a 4-Way harness if you don't already have one. For this I recommend the Tekonsha T-One Vehicle Wiring Harness # 118467. This custom harness will simply plug into factory ports located in the rear cargo area on the Outback. I have attached an installation video that you can use for reference. Then with the 4-Way installed (or if you already have one on the vehicle)...
    view full answer...
  • Parts Needed to Install a Brake Controller and 7-Way in a 2012 Lincoln Navigator
    Yes, the Curt Trailer Connector Adapter # C57102 would be the correct part for you to use to convert your 4-way to a fully functional 7-way. You would just need to run the wires of the # C57102 to those leads. If there isn't a 12 volt power lead you will need to run a 10 gauge wire like part # 10-1-1 through a 40 amp circuit breaker like part # 9510. The brake controller we recommend the most is the Prodigy P2 Brake Controller part # 90885. This is the best selling controller on the...
    view full answer...
  • Parts Needed to Add a Trailer Brake Controller on a 2000 Toyota 4Runner
    The information I have on a 2000 Toyota 4Runner is that a brake controller has to be hardwired in so you would follow the instructions in the FAQ I have linked. The black wire on # C57102 will connect to the positive battery terminal via a 40 amp circuit breaker # PK54540. The white wire will ground to the vehicle frame. The yellow wire will connect to the reverse light circuit if the trailer has reverse lights. The blue wire will connect to the blue wire from a brake controller. For...
    view full answer...
  • Factory Trailer Wiring Harness Connection Point on a 2001 Toyota Highlander
    If your 2001 Toyota Highlander came with a factory tow package then there is a connection underneath. But if it did not come with a tow package the connector will either A) not be there or B) not be functional. On vehicles that have the connector it is located behind the rear bumper. On some, it is located behind the bumper and inside of a plastic box. Take a look at the instructions I have linked for harness # 118245 which should help you locate the harness if it is present on the...
    view full answer...
  • Does the Backup Alarm on Curter Trailer Connector Adapter # C57102 Sound Just when Towing
    Any time the vehicle is placed in reverse, whether you are towing or not, the alarm will sound. You will have to make sure that yellow wire is connected to a reverse light wire on the vehicle in order for the alarm to function.
    view full answer...
  • How Does the Curt Connector # C57102 Wire Up
    After you plug the 4-way in from your 2006 Ford E-350 to the Curt Trailer Connector Adapter # C57102 you will need to run the rest of the wires as follows: The white wire will need to be grounded to a clean metal surface. The blue wire will go to the brake output signal of your brake controller. The black wire will go to the positive side of your battery through a 40 amp circuit breaker like part # PK54540 The yellow wire will run to the reverse light circuit.
    view full answer...
  • Installation of the Curt Trailer Connector and Back-Up Alarm # C57102 on a 2001 Jeep Grand Cherokee
    Yes, you can connect the yellow wire of the Curt Trailer Connector and Back-up Alarm, # C57102, to the back-up light circuit on your 2001 Jeep Grand Cherokee. Connecting the yellow wire will allow the back-up alarm to activate when you put your Jeep in reverse.
    view full answer...
  • Where to Tap Into Reverse Light Circuit to Install Trailer Connector Adapter with Backup Alarm
    To wire in the reverse light wire on Curt 7-Way connector # C57102 for the back up alarm to work you will need to tap into a reverse light wire behind a reverse light on your 1999 Dodge Ram. If you do not wish to tap into the wire there then you can trace the harness to a more accessible location. Then use a circuit tester such as # PTW2991, to find the correct wire before tapping into it. Be sure that the white ground wire on the 7-Way is attached to the truck frame. Otherwise the...
    view full answer...
  • Do All 7 Circuits of 7-Way Need to be Ran When Installing Brake Controller
    So the first thing you should note is that if you don't need a reverse light circuit or an accessory circuit you don't have to complete those wires. You can leave those off for most situations. Normally the 12 volt power wire runs to the positive post of the vehicle battery with 10 gauge wire like part # 10-1-1 (sold by the foot) through a breaker like part # 9510 and then the reverse light circuit runs to the reverse lights of the vehicle tapped in with a quick splice like part # SWC501746-1....
    view full answer...
  • Adding a 4- or 7-Way Trailer Connector to a 2017 Chrysler Pacifica
    The trailer wiring harnesses for the 2017 Chrysler Pacifica do not require identifying the tail light wires and splicing in a harness. There are a couple of options depending on the trim level of your Pacifica. If you have a Limited model use # 118712. And if you have an LX or Touring model use # 118723. Both of the above harnesses are 4-Ways. To add a 7-Way you would first need to install one of them. Then to add a functional 7-Way, retain the 4-Way, and to have the wiring for a brake...
    view full answer...
  • What are the Wire Functions of the CURT Trailer Connector Adapter, # C57102
    You are correct. On the CURT Trailer Connector Adapter, # C57102, the white wire is ground, black is for 12 volt power, blue is for brakes, and yellow is for reverse lights. The 4-Way would then just plug into a 4-Way trailer connector on the vehicle to provide the remainder of the lighting functions. Be sure to ground the white wire to the vehicle frame for the connector to function properly.
    view full answer...
  • Could 4-Way to 7-Way Adapter with Reverse Alarm Fit 2020 Honda Odyssey with 4-Way
    Yes if you wanted to use the # C57102 as a way to convert your 4-way to a 7-way and install the brake controller you mentioned. You will need wiring to run from the brake output of your brake controller to the blue wire of this adapter. We have 10 gauge wire for this with # 10-1-1 which we sell by the foot.
    view full answer...
  • How To Get A 7-Way and 4-Way Trailer Connector On A 2012 Ford F150 With Only a Factory 4-Flat
    If under your rear bumper you have in addition to the 4-pole flat connector additional unterminated wiring for a 7-way you can use Curt # C57102 to convert your Ford F-150 4-pole flat trailer connector to a combination 4-pole and 7-pole trailer connector. This part includes the additional feature of a backup alarm, which is activated simply by connecting the yellow wire to the reverse light circuit, if desired. The alarm will sound when the F-150 is shifted into reverse gear. If you prefer...
    view full answer...
  • Universal Version of the Curt Trailer Connector # C57101
    The closest thing we have to a universal version of the Curt Trailer Connector # C57101 would be the Curt Trailer Connector Adapter # C57102. This adapter is designed to plug into a 4-way and then the other 4 wires would get run to where they belong. White to ground Blue to brake controller output Yellow to reverse light circuit Black to positive side of the battery
    view full answer...
  • Does Curt Echo Brake Controller Need to be Level with Ground
    The Curt Echo Brake Controller # C51180 referenced in your question does not need to be at any particular angle in relation to the ground for proper operation. The controller simply needs to be plugged into the 7-Way on the tow vehicle and it will work as it should. When converting your 4-Way to a 7-Way with an adapter like the Curt # C57102 you will only need to run the 12V power wire up to the vehicle's battery like you mentioned. The brake output pin on the 7-Way does not need to...
    view full answer...
  • Parts Needed to Tow Trailer with 2014 Toyota Sienna
    To install the Prodigy P3 part # 90195 in your 2014 Toyota Sienna you could use the # 5506 and the # C57102 that you referenced and you'd be set. This would give you basically the same kit as the # ETBC7 except with the backup alarm. You wouldn't need the # ETBCXW either. With transmission coolers the best option is to go with the largest one that will fit in the available space in front of the radiator. For example the part # D13503 measures 11" Wide x 8-3/4" tall x 7/8" deep and would...
    view full answer...
  • Recommended Backup Alert for 2017 Ram 1500 Laramie Longhorn
    The Hopkins Backup Alert - Replacement 3156 Bulb with Audible Alert # HM20101VA is not a fit for your 2017 Ram Laramie Longhorn 1500 Crew Cab 4x4. For an audible alert you can use the Light-Duty to Medium-Duty Back-Up Alarm with Wire Leads # PK41822, the medium to heavy-duty # PK41851, or the integrated alarm in the Curt Trailer Connector Adapter with Backup Alarm - 4-Way to 7-Way RV and 4-Way Flat # C57102. Let me know if you need other options, but unfortunately we don't have...
    view full answer...
  • Install a Curt Trailer Connector Adapter with a Backup Alarm on 2000 Chevy C3500 Cab and Chassis
    It is highly likely that there is an OEM pigtail wiring harness that you could plug the Curt # 57101 into on your 2000 C3500 Truck. The typical locations for this connection point are near the spare tire and also on the drivers side behind the rear tire on the frame rail. This connector will most likely have a dust cover on it and you should be able to remove the cover and the zip ties holding this to the frame and plug it directly into the connector on the rear of the Curt Trailer connector...
    view full answer...
  • Will the the Hopkins Back Up Alarm Fit both a Ford 2009 F-150 as well as a Ford 2013 F-150
    I have checked with my contact at Hopkins, and it looks like both the 2009 and 2013 Ford F-150 use a 921 bulb. Hopkins does not currently have a back up alarm system that is compatible with this tail light bulb style. If you would like you could use the Curt # C57102 or the #C57101. These are replacment trailer connectors that have also have a back up alarm included. If your trucks currently have a factory installed 7-way you will want to use the # C57101 as a direct replacement. If...
    view full answer...

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Info for this part was:

Written by:
Lindsey S
Expert Research:
Michael H
Expert Research:
Jameson C
Updated by:
Sarah W
Updated by:
Amanda M
Updated by:
Kristina F
Updated by:
Isabelle B

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