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Universal Wiring Adapter for Curt Trailer Brake Controllers

Part Numbers: C51515


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Curt Accessories and Parts - C51515
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Universal Wiring Adapter for Curt Trailer Brake Controllers
part number: C51515

This wiring adapter is designed for vehicles that do not come equipped with a factory brake control wiring harness port. One end plugs into your Curt trailer brake controller while the other end splices into your vehicle's wiring.


  • Universal wiring adapter eases installation of your electric trailer brake controller
    • No need to wire brake controller directly to your vehicle
  • Wire end splices into your vehicle's wiring
    • Use on a vehicle that does not have a factory tow package or on one that has a brake control harness but is not equipped with a plug-in port
  • Connector end joins with the plug on your electric brake controller
    • Compatible with time-delayed and proportional brake controllers from Curt
    • Simple to plug and unplug control for removal
  • 2' Long, 12-gauge wires have protective covering to deter damage
  • Limited 1-year warranty

Installation of Curt Brake Controller Adapter

To install your Curt electric brake controller, you need to connect the wiring of the controller to your vehicle. Certain auto manufacturers offer pre-wired options, typically known as tow packages, wherein wiring is run for you from the dash to the trailer connector on the back of your vehicle. Usually when this is done, a port is installed at your dash so that you can easily plug in a brake controller. However, if no port is present, you will have to splice into your wiring.

With this universal adapter, you can install your Curt brake controller without having to wire the controller directly to your vehicle. If your vehicle has a factory tow package, just splice the pigtail end of the adapter into your vehicle's factory brake control harness wiring, and then plug the other end of the adapter into the controller. If your vehicle doesn't have a factory tow package, you'll have to hardwire the pigtail end of the adapter into your vehicle's wiring. Because only the adapter is hardwired to your vehicle, you can unplug and remove your brake controller at any time to transfer it to another vehicle or securely stow it away.

If your vehicle is not equipped with a factory tow package, you will need to purchase additional equipment to ensure that the signals from your brake controller are sent to your trailer's brakes. We recommend's exclusive 7- and 4-way brake control installation kit (ETBC7 - sold separately).

51515 Curt Universal Quick Plug Brake Control Adaptor Harness with Pigtail

California residents: click here

Video of Universal Wiring Adapter for Curt Trailer Brake Controllers

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

Video Transcript for Curt Brake Controller C51515 Review

Today we're going to review part number c51515. This is the CURT universal wiring adapter for CURT trailer break controllers. Now, this adapter will plug into your CURT trailer break controller at one end. The other end with the pig tails would splice into your vehicle's wiring. This universal wiring adapter eases the installation of your electric break controller to your vehicle. There's no need to wire the broke controller directly to your vehicle.

You'll be able to plug it in right here, and then if you need to remove it you can unplug it and remove the break controller. This end right here will splice into your vehicle's wiring. This is designed to be used on a vehicle that does not have a factory tow package or on one that has a break control harness, but is not equipped with a plug in port. The connector end joins with the plug in your break controller. This is compatible with a time delayed and the proportional break controllers from CURT. Simple to plug and unplug for removal.

It is about a two foot long wire. They do use twelve gauge wires with a protective coating to prevent damage, and it is in a wire loom. Basically, does have a tag on it that shows you the colors and where they do attach. Basically, the black is the battery power. The white is the ground.

The red would be the break signal from the vehicle. The blue is the electric break feed to the trailer. That should do it for the review on part number c51515. This is the CURT universal wiring adapter for the CURT trailer break controllers. .

Customer Reviews

Universal Wiring Adapter for Curt Trailer Brake Controllers - C51515

Average Customer Rating:  4.8 out of 5 stars   (219 Customer Reviews)

This wiring adapter is designed for vehicles that do not come equipped with a factory brake control wiring harness port. One end plugs into your Curt trailer brake controller while the other end splices into your vehicle's wiring.

- C51515
by: Christopher03/12/2018

The items I ordered I got in a timely manner great job 484308

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by: Robert09/30/2018

Product was easily located on website and was exactly what I was looking for. I had forgotten to take off of my old vehice before I sold it, so this allows me to plugin my Curt brake controller without having to cut the connector off of it. 570389

- C51515
by: Mainly Dave07/22/2015

Recently used this kit to install electronic brakes on a 2014 FJ Cruised. Absolutely essential and worth every penny! Instructions straight forward and everything included! 213491


Have been using this product for a year now. Commonly haul 2-3 tons. Absolutely no problems and the braking system works well. Adjustments based on load are easy. Highly recommend!

Mainly D - 07/22/2016


- C51515
by: BiscuitsNGravy10/21/2013

I own a 2008 Chevy Silverado. I ordered the brake controller - C51515 and the universal wiring adapter on Friday and received it on Tuesday. My friend who is a mechanic installed it in about an hour on Wednesday. I towed my camper trailer to Lincoln, NE (about a 5 hour trip) on Thursday and returned on Sunday. After reading the settings instructions, all stops were made smooth and firm. was great and the Curt Trailer Brake Controller is excellent! 104632


I have enjoyed the use of the electric brake controller. The stops are always safe and smooth. Im glad I got it for my truck and Ive never had a problem with it. I just need to get out and use my camper more! The initial contact with was very favorable and I will do business with them again when I need something for my trailers or tow vehicles.

BiscuitsNGravy - 10/21/2014


- C51515
by: Frank S02/14/2014

this went into my VW Touareg which requires the relay modification described in the Technical Bulletin. Because ground and +12V is already present in the harness, instead of running additional cables, I soldered the relay right into the cable, making it a clean plug and play setup which is 100% removable. I also bought the VW housing and wire kit to complete the install 116584

- C51515
by: George D10/17/2015

good quality and works with brake controller so you don't have to rig it up its all there glad i bought it thanks 230175


Very easy to do still working great

George D - 10/16/2016


- C51515
by: Kent E.06/05/2016

Wiring up a brake controller can be tricky. Routing the wire from the hitch to the firewall and finding the right wire on the brake are the hardest part, but etrailer will do their best to help. Consider running the wire inside the car along the door bottom just under the carpet. This avoids problems with the tie-wraps under the car -- there just isn't anywhere to tie wrap under the middle of the car. Use "loom clamps" ordered separately to solve this problem, if you go under the car. To find the right brake wire without cutting insulation, use the fish wire from the hitch install to contact the end of the wire inside the connector (from the back). Then touch the fish wire with the continuity tester and apply the brake pedal. My brake had a four wire connector and I found the right one on the second try. If you find a hole in the firewall with a rubber plug in it, don't discard the plug. Make a short slice in it with a razor blade and push the wires through. You may have to work the wires around to get them through the carpet. Be patient. Be sure to watch all the videos and allow plenty of time, taking a break before you tackle the hard parts. Rest assured that doing it yourself is better than allowing UHaul to cut corners and charge you labor. :-) If you are doing the hitch install and four-wire harness, those are much easier. If you are installing the hitch alone, be sure to have a magnet wand for when you push the bolt up into the frame rail. If I had it to do again, I would use a little electrical tape to hold the bolts down so a slight bump wouldn't knock them up. 257414


Ive not had any trouble with the hitch or the brake controller. I can tow my tear trailer anywhere I want and the hitch protects my mufflers from damage when I go offroad. Nice extra benefit.

Kent E - 01/23/2018


- C51515
by: Ted07/03/2014

I purchased the wiring harness to aid with hooking up the Curt Brake Controller I had previously purchased. The shipment was fast. The product was perfect. The on-line installation video was perfect and allowed me to complete the installation like a professional. I have never purchased anything from .... but should I ever need anything in the future, they will be my first choice. 139007


Perfectly. No issues at all with wiring or controller.

Ted - 07/03/2015


- C51515
by: Marc04/27/2019

Installed this brake controller last weekend. etrailer has helpful videos that also include associated products with part numbers. Watching the video and checking other references confirmed I needed the wiring harness, too. So I ordered both and it made the install go smoothly. 635468

- C51515
by: Alan04/20/2019

Easily installed 633763

- C51515
by: David03/27/2019

Not much to say about this. Is what it is. Plugs in to the curt triflex brake controller nice and firm. A little longer (it’s about 2’ long) than I needed in my 2011 Silverado but the excess wire tucked away nicely. 614612

- C51515
by: Chris03/27/2019

Great quality. Thank you again. 614577

- C51515
by: Humphrey,02/15/2019

Easy install 605452

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by: Jon02/11/2019

This made to real simple for the connec tions. 604158

- C51515
by: Scot02/03/2019

Great parts at a great price. 602453

- C51515
by: Larry01/24/2019

The plug fit my controller making it easier to hook up 599972

- C51515
by: Doug12/05/2018

I works great. Top quality! 588424

- C51515
by: Jim11/13/2018

Works well. 582452

- C51515
by: Jonathan K.10/20/2018

I am completely satisfied. The package arrived quickly and I was able to install on my truck the same day with help from the installation videos. I will definitely purchase from in the future. I have saved money by spending with and doing the upgrades myself. 576833

- C51515
by: Trevor10/03/2018

Simple and easy to install. Helps make a cleaner look 571173

- C51515
by: Jeff09/18/2018

made wiring painless 566423

- C51515
by: Robert08/21/2018

Packed well and delivered on time. Easy installation, and Etrailer always provides additional resources if you get stuck and need help. Great company 556678

- C51515
by: Ross08/17/2018

Easy to use, great customer service. 554693

- C51515
by: Noob07/20/2018

Great product, makes a brake controller install easy. 543674

- C51515
by: Robert07/10/2018

This was my first purchase from etrailer. I will definitely come back again and again. Fast shipping. You all are great. Thank you so much. 540026

- C51515
by: Matt06/18/2018

Works very well! Nice product and easy install! Very satisfied! 523773

- C51515
by: Peter06/17/2018

Excellent fantastic service. 522824

- C51515
by: Don06/11/2018

Great quality product ! 520809

- C51515
by: Cliff06/08/2018

Worked great and went on very easy. Feels a lot better to tow a trailer with brakes!! 519530

- C51515
by: James06/01/2018

Easy install, nothing to it! 515410

- C51515
by: Brandon05/16/2018

Product works as should. Good understanding of how to install based on video for trailer brake installation. Had some issues trying to find the cold wire off brake controller in car. Reached out to etrailer for help and they had not installed before on kia sedona so did not get much assistance. Was able to find with circuit probe and placing clothes pin into plug. Overall happy with product 509085

- C51515
by: Jim C.04/09/2018

Ordered the wire harness for my GMC Envoy to be used on the Curt Tri-Flex brake controller. It did not have instructions as to how to connect the wires to my vehicles wire harness, but I viewed the youtube video they have it answered any questions I had. It showed where to find the correct wires and how to connect them. This was my second order to etrailer and they have never let me down. The parts are of good quality, fast service and technical help. After I find my RV,, etrailer will be my first stop to look for a hitch. 494505

- C51515
by: Dennis04/07/2018

Works great, easy install 494380

- C51515
by: Mia04/03/2018

good price 492254

- C51515
by: Brennan03/31/2018

Made the install in my Silverado easy. 4 wires and done 491279

- C51515
by: Dave03/19/2018

This product was delivered on time about a year ago. I also ordered the installation kit and it went together great works great and I’m very happy with it. 486998

- C51515
by: Zachary03/11/2018

I ordered all the equipment to help my son rewire his enclosed trailer. We got everything as ordered and it all worked out great. I had emailed etrailer multiple times to discuss what exactly I needed. They were great and their help was above and beyond. Any trailer parts, wiring, etc., you need, this is the place to get it! 483868

- C51515
by: Curt02/16/2018

A must have 476512

- C51515
by: Dennis02/15/2018

Great and easy 475944

- C51515
by: Adam01/24/2018

Ok 469231

- C51515
by: Ross01/13/2018

Very nice product. It made wiring the brake controller in an easy task. 467062

- C51515
by: Bernard01/06/2018

Arrived in excellent condition. Very short wait time! 465210

- C51515
by: David01/05/2018

Harness hooked right up and it's only 15 Dec. so that meant a lot. The only problem I had was with the post office losing the first one and taking for-never finding it. These people really took care of me and stay in contact with me throughout the entire process. Great work and thanks very much. 465108


Great, it really made the wiring for my trailer A lot easier and it still working fine. Toyota Tacoma are noted for their, lets say, interesting way you have to put in a towing package with the wiring being sometimes a problem.

David - 01/05/2019


- C51515
by: Dennis12/29/2017

I have not installed it yet but it is what I expected. It is a pleasure doing businesses with these people, always prompt and upfront with EVERYTHING. Buy from them, you won’t be disappointed. 463609

- C51515
by: Alan11/17/2017

Too short! Had to splice extra wire to reach into engine compartment. 2003 Ranger XLT 452858

- C51515
by: Elmer11/09/2017

Ordering and shipping was quick and painless. 2nd time around ordering from them again and it was great 450679

- C51515
by: Jarratt Blackburn10/15/2017

Awesome product it's very nice to have an adapter harness to wire into your vehicle that plugs into the trailer brake controller that way if there is ever an issue with the controller you just unplug it. 442882

- C51515
by: Jared S10/12/2017

Worked as advertised. 442039

- C51515
by: Dan10/03/2017

Should work haven't installed yet. 438851

- C51515
by: Matt w09/27/2017

Fast shipping. Easy to install. Works g reat. 436944

Show More Reviews

Ask the Experts about this Brake Controller
Do you have a question about this Brake Controller?

  • Troubleshooting Curt Brake Controller Installation in 2007 GMC Sierra New Body Style
  • First I suggest making sure you are testing the brake circuit pin on your Sierra's 7-way trailer socket. If you refer to the linked photo of a trailer connector you will note the brake controller's output is carried on the pin at the 5:00 position; the ground is at the 7:00 position. If you happened to test the 12V auxiliary power circuit, carried on the pin at the 2:00 position, it will have power at all times. I see that you purchased Curt Universal Wiring Adapter # C51515 which
    view full answer...

  • Adapter for Curt Venture Brake Controller on VW Touareg
  • In order to use the Universal Wiring Adapter for Curt Trailer Brake Controllers # C51515 with your Curt Venturer # C51110 brake controller, you will need additional parts from your Volkswagen dealer. Please see the attached help article on installing a brake controller in 2005 and up Volkswagen Touareg's. It states in part: "To install a brake control on a 2005-current Volkswagen Touareg or Porsche Cayenne using the factory brake control connector, you will need to assemble a brake
    view full answer...

  • Brake Controller Recommendation for a 2012 Mercedes GL450
  • In order to install a trailer brake controller on your 2012 Mercedes GL450 it will require hardwiring in the controller unless the Mercedes dealer has a wiring harness specific for a brake controller and your vehicle. If they do then you will need to wire in the controller to the Mercedes harness by function. On a brake controller, the wire functions are as follows: White is ground Black is 12 volt power Blue is output to the trailer brakes Red is input from the brake switch On
    view full answer...

  • Brake Control Harness # 51515 Installation Process in 2008 and 2013 Chevrolet Silverados
  • The Curt Brake Controller Harness you referenced, part # C51515, can be used for both the 2008 and 2013 model years of the Chevrolet Silverado since it is a universal-fit harness. For your 2013 Silverado you will want to follow the procedure outlined in the linked article. Please refer to the photo provided which shows the vehicle tow package wiring that can be found under the dash. You will connect these wires to the leads on the Curt harness as per the article, using butt connectors
    view full answer...

  • Brake Controller and Install Harness Recommendation for a 2006 Jeep Commander
  • The correct Curt brake controller install harness you will need for your 2006 Jeep Commander is the part # C51515 that you referenced. I would recommend you go with a proportional brake controller with it like the Curt Triflex part # C51140 as it will sense the amount of braking you are applying with your vehicle and will provide a proportional amount of braking power to the trailer. Some models will require a wiring kit to run wire to the battery. This may require drilling a hole
    view full answer...

  • How to Install the Curt Wiring adapter # C51515 on a 2008 Chevrolet Silverado
  • To install the Curt Wiring adapter # C51515 in your 2008 Chevrolet Silverado you will need to hardwire it under the dash. To be sure that the wire bundle you found under the dash is the correct set of wires I would check the white tag for any indication as to what each wire is for. If none of them have labeling then it would be best to test their functions with a circuit tester like part # PTW2979. You will then connect the following wires from the Curt adapter to the following functions: Blue
    view full answer...

  • Wiring Adapter for Curt Electric Brake Controller on 2016 Toyota Tacoma
  • We do offer the Universal Wiring Adapter for Curt Trailer Brake Controllers # C51515. This adapter will connect with the plug on the back of the Curt electric brake controller on one end and the other end will allow you to hardwire install the brake controller. If you need to add a 7-Way to your tow vehicle, the # C51515 adapter will work well with the Universal Installation Kit for Electric Trailer Brake Controller # ETBC7. The instructions for this hardwire installation are linked
    view full answer...

  • When Does Brake Output Circuit of Vehicle 7-Way Have Voltage
  • The brake output circuit on a 7-way (5:00 pin) will only have as much voltage on it as the brake controller is sending. Typically this going to depend on the amount of gain selected on the controller and other factors like brake controller style and ramp up speed of the controller. The only time the circuit would have voltage without the brake pedal being applied would be if you had the manual override lever of the controller slid. I attached a couple help articles on brake controllers
    view full answer...

  • Troubleshooting Brake Controller Not Allowing Truck To Start
  • For your 2014 Chevy Suburban, no plug is present under the dash, but the needed wires are already run. You will connect the brake controller wiring with the vehicle wiring already present under the dash using the Universal Wiring Adapter for Curt Trailer Brake Controllers # C51515. It seems the 2007 to 2013 brake controller wiring was carried over into 2014 for your vehicle. I've attached and article to assist. The issue you are experiencing is most likely because you have a plug
    view full answer...

  • Custom Wiring Adapter for 2012 Chevy Silverado Curt Brake Controller
  • If you are looking for the custom adapter for the Curt Reflex Trailer Brake Controller # C51130, you will need the Universal Wiring Adapter for Curt Trailer Brake Controllers # C51515. Unfortunately, no factory plug is present under the dash on your truck, but the needed wires are already run. You will connect the brake controller wiring with the vehicle wiring already present under the dash. It is a two foot long wire. These are twelve gauge wires with a protective coating to prevent
    view full answer...

  • Troubleshooting Curt Venturer Brake Controller Installed on 2011 Dodge Ram 1500 Pickup
  • Getting a single green LED on the display indicates that there's no trailer connected. Since you're getting this with the trailer connected, it would seem to indicate that the brake controller isn't 'reading' the trailer for some reason. The most common reason for this to happen would be a dirty, corroded or damaged connector on the vehicle or the trailer. Examine the trailer connectors, and ensure everything is clean. If you see any white or green corrosion on the pins or sockets of the
    view full answer...

Info for this part was:

Edited by:
Leah B
Expert Research:
Michael L
Video by:
Andrew K
Written by:
Lindsey S
Expert Research:
Michael H
Installed by:
Jeff D
Expert Research:
Jameson C
Video by:
Joshua S
Test Fit:
Nicholas E
Video Edited:
Andrew L
Expert Research:
Adam R
Video Edited:
Dustin K
Photos by:
Jim W
Test Fit:
Shane T
Video Edited:
Sue W
Video Edited:
Chris R
Updated by:
Sarah W
Test Fit:
Brent H
Updated by:
Kristina F

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