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Universal Wiring Adapter for Curt Trailer Brake Controllers

Universal Wiring Adapter for Curt Trailer Brake Controllers

Item # C51515
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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. 1-800-496-5010 to order CURT accessories and parts part number C51515 or order online at Free expert support on all CURT products. Guaranteed Lowest Price and Fastest Shipping for Universal Wiring Adapter for Curt Trailer Brake Controllers. Accessories and Parts reviews from real customers.
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CURT Accessories and Parts - C51515

  • Trailer Brake Controller
  • Wiring Adapter
  • Plugs into Brake Controller
  • CURT
  • Universal

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

Customer Reviews

Universal Wiring Adapter for Curt Trailer Brake Controllers - C51515

Average Customer Rating:  4.8 out of 5 stars   (372 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.


This is a "must have" if your vehicle did not come with a "tow package". If your vehicle does have a tow package try to get the correct wiring adapter and you can just plug it in without having to make wiring connections.

So far, so good!
Peter - 06/23/2022


Awesome customer service!! Installed trailer brake control on my 2018 Chevy Colorado . Install was a breeze, control knob is small and out of the way and it works perfectly!


The Curt Spectrum Brake Controller works great for my 2008 Toyota Highlander. I mounted it on the front of the console armrest compartment behind the cup holders (facing forward). I was easily able to route the wiring out the bottom of the console and access the module under the drivers seat (be very careful installing the pins into the clip, they are very fragile). Then I ran the wires under the bottom edge of the console and out through the fire wall (Be very careful drilling your hole through the firewall. I caused some damage I had to have repaired}.
Also, the help I had from Yolanda, making sure the kits I needed were compatible, was extremely important because I was leaving for a cross country trip later that week. She was wonderful and everything worked great for my trip.
Thank you etrailer. I'm a regular customer and will remain so.


I have the Dodge Ram Truck 94 model with factory wire 7 connector plug. This is the truck that many people can't find the blue wire under the dash. 94 model didn't come with a factory wire plug under the dash like later models have. I found the wire tape to the main wiring harness about two inches from the fire wall to the right of the emergency brake paddle. This harness worked great


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


Easy to install and well written installation instructions.


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.

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


Works well, I am very happy with it.


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!

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


It made the installation a breeze


I bought a 7 pin trailer wiring/brake connection for my Dodge pickup. I installed it myself, the instructions were absolutely clear and correct. It was an easy installation. In the year since, I've pulled my trailer (tandem axle, 16') many times. The brakes continue to work perfectly as well as the lights. The connectors are solid, all work just like new. I recommend Etrailer parts and their people 100%!

Still working great. Not any problems. A great product
Howard S - 04/06/2018


This is much more convenient than directly wiring into a 51170, especially for trucks with factory installed hitches.


Worked like a charm. The right part for a fair price.


Made it easy to wire. Simple to plug into controller.


Easy hook-up and connection.


Easy to install, just have to verify wiring colors (different than wiring harness colors on vehicle that could be confusing to some.)


This was a pain in the a** after getting it wired I took it off an ordered the correct part from online


Product works as it should


Very detailed trail of information of the information about the delivery. most informative! Excellent service.


etrailer is the tough version of crutch field


Spoke with etrailer on the phone, they helped me get the right hitch for my car. The hitch was good quality, and their install video really helped.
They shipped promptly and everything arrived in just a few days.
Great experience.


Worked like it should. You might leave the sleeve uninstalled on the 4 wires for the installer to fit. I only needed it for the 2 wires going through the firewall. It was not useful for the ground and switch wire.


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!

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


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.

Perfectly. No issues at all with wiring or controller.
Ted - 07/03/2015


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.

Show More Reviews

See what our Experts say about this CURT Accessories and Parts

  • White Ground Wire Is Taped To Orange Wire 2009 GMC Sierra 1500 Brake Controller Install
    You want to use the white wire in your photo for the ground. The other orange wire is the CHMSL circuit which stands for center high mount stop light wire. It is not used by a brake controller so you can tape it up and stow it out of the way. You will need 4 wires to install the brake controller, 12 volt power (red and black in your photo), trailer brake output (solid blue in your photo), stoplight circuit (light blue with stripe in your photo) and ground (white).
    view full answer...
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  • 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 that...
    view full answer...
  • 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 installs...
    view full answer...
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  • 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...
  • Curt Wiring Adapter For A Brake Controller Compatible With Vehicles Without A Factory Wiring Plug
    Yes we do, The Universal Wiring Adapter for Curt Trailer Brake Controllers, part # C51515, is designed to work with Curt Trailer Brake Controllers on vehicles without a factory brake control wiring harness. These wires will have to be spliced into your vehicle's existing wiring, so there should be no issue with your 2004 Toyota Tacoma. I have included a product description link, a video installation link, and a video review link below.
    view full answer...
  • Will Tekonsha Wiring Harness # 22114 Work with a Curt Brake Controller and 2015 Ford Transit
    Trailer wiring harness # 22114 will fit your 2015 Ford Transit and it will work with your Curt brake controller. The brake controller will be hardwired in since the vehicle does not have a factory tow package. So instead of using the harness that comes with the kit to hardwire in the controller you would need the Curt version, # C51515, if you don't already have it. I have included some links that will help with the installation. You will be looking at the parts relating to hardwiring...
    view full answer...
  • Wiring Harness for Curt Spectrum Brake Controller on 2019 Volkswagen Atlas
    The wiring adapter you need to use the Curt Spectrum Trailer Brake Controller # C51170 in your 2019 Volkswagen Atlas is the Universal Wiring Adapter for Curt Trailer Brake Controllers # C51515. This is a splice-in adapter because there is not a plug-in adapter available for your '19 VW Atlas, for the Spectrum or for any other brake controller. I have added links to video reviews for you to take a look at as well.
    view full answer...
  • 2014 Cadillac Escalade Won't Start After Curt Brake Controller Installation
    Thanks so much for the purchase from us of the Curt Discovery Trailer Brake Controller # C51120 for your 2014 Cadillac Escalade, and I'm sorry to hear of this issue you are having. This controller, which you'd use with Wiring Adapter for Curt Trailer Brake Controllers # C51515 assuming the Escalade had a factory 7-way already, should not have anything to do with the vehicle starting or not, which means there was a mistake somewhere along the way with the wiring process. I have added a...
    view full answer...
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  • Will the Curt TriFlex Trailer Brake Controller Fit a 2018 Chevrolet Colorado
    Yes, the Curt TriFlex Trailer Brake Controller part # C51140 will fit a 2018 Chevrolet Colorado when used with the Universal Wiring Adapter for Curt Trailer Brake Controllers part # C51515. Please note, if your truck came with the factory 7-way then all the wires you need to use are already run under the dash.
    view full answer...
  • Can Curt Spectrum Brake Controller Install in 2011 GMC Yukon
    The Curt Spectrum part # C51170 can install easily in your 2011 GMC Yukon with the factory wiring it has under the dash with the universal wiring harness part # C51515 but like you mentioned it has to wire directly to the brake controller wiring under the dash as there isn't a connector present for a plug-in type install. To see how a similar brake controller installs in a Yukon like yours check out the install video link I attached to this page.
    view full answer...
  • Does the Curt Spectrum Work with Adaptive Cruise Control and Safety Emergency Braking
    The Curt Spectrum # C51170 is a proportional brake controller, meaning that the brakes on the trailer are applied in proportion to the amount of inertia sensed by the slowing of the vehicle. So to answer your question, it's going to sense small slow downs and lightly apply the trailer brakes, but will also respond when you brake the vehicle using the brake pedal and apply the brakes on the trailer as well. This is going to work regardless of whether you've got the adaptive cruise control...
    view full answer...
  • Comparing the Curt Reflex and Curt TriFlex Trailer Brake Controllers
    The main difference between the Curt Reflex Trailer Brake Controller part C51130 and the Curt TriFlex Trailer Brake Controller part # C51140 is that the TriFlex has a triple-axis accelerometer with nine boost settings and the Reflex has a dual-axis accelerometer with four boost settings. The triple-axis accelerometer is going to provide more uniform braking than the dual-axis accelerometer and the extra boost settings are going to allow you to really fine tune the braking power output to...
    view full answer...
  • How Does Brake Controller Install in 2011 Chevy Colorado
    Yes it is that simple! To wire in a brake controller to your 2011 Chevy Colorado only requires you to wire the four wires of the controller to the 4 wires that are present under the dash of your truck. I attached an install video that shows this process on a similar 2015 Colorado.
    view full answer...
  • Parts Needed to Install Curt Discovery Brake Controller in 2014 Chevy Tahoe
    To install the Curt Discovery brake controller # C51120 in your 2014 Chevy Tahoe you'll need the install harness part # C51515. This wires to the blunt cut wires that are under the dash of your Tahoe. To see how it installs check out the install video that shows this controller installed in a similar 2015 Chevy Tahoe.
    view full answer...
  • Do I Need a Brake Controller for a 2007 Chevy Tahoe with Tow Package Towing a 2017 Jayco Baja
    Assuming your trailer has brakes, you may still need a brake controller. GM started putting factory brake controllers in their trucks and SUVs in 2007, but it was an option. The factory brake controller did not come standard with the tow package. If you have a factory brake controller, you will see a black square with a horizontal lever and two buttons (+ and -) just below your light controls to the left of your steering wheel. If you don't have that, then you will need to add a brake...
    view full answer...
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  • 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 control...
    view full answer...
  • Compatibility of Curt Discovery Brake Controller With 2010 Chevy Silverado
    Brake controllers are not vehicle specific. The # C51120 Curt Discovery brake controller is compatible with your 2010 Silverado. You'll also need the Universal Curt Brake Controller Pigtail, part # C51515. The pigtail wire will connect directly to the tow package wiring located under the dash between the steering column and the emergency brake pedal. Look for a bundle of wires with a white tag hanging from it. The wires of the pigtail will connect to the tow package wiring as follows: Red...
    view full answer...
  • Installing a Brake Controller in a 2009 Chevy Suburban
    The 2009 Chevy Suburban does not have a port to plug in a brake controller which is the same as the trucks of the same year. But it does have the tow package wire bundle up under the dash, to the left of the steering column, held together with a white tag. Pull the wire bundle out to wire in a brake controller. With Curt brake controller # C51120 you will also need pigtail # C51515. Then you can make the following connections: Vehicle red/black wire to controller black wire for 12 volt...
    view full answer...
  • Installing Curt Brake Controller on 2007 Chevy Silverado New Body
    It sounds like you have the correct harness for your Curt Venturer Brake Controller # C51110 and your 2007 Chevy Silverado, which is the Wiring Adapter Harness # C51515. This particular harness does feature a plug on one end that connects to the brake controller itself but as you mentioned the other end features bare wires. This is because the 2007 Chevy Silverado should have bare brake controller wiring, not a plug, under the dash that these wires will connect to. It's possible that...
    view full answer...
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  • Wiring Adapter to Install Curt TriFlex Trailer Brake Controller C51140 in 2009 GMC Sierra
    You can re-install your Curt TriFlex Trailer Brake Controller # C51140 in your 2009 GMC Sierra by using the matching wiring adapter # C51515. No plug is present under the dash, but the needed wires are already run. You will connect the brake controller wiring from C51515 with the vehicle wiring already present under the dash. Please refer to the linked video.
    view full answer...
  • Installation of Curt Venturer Electronic Brake Controller in 1999 Chevrolet S-10
    To install the Curt Venturer Electric Brake Controller # C51110 you definitely need the red wire. Black to 12 volt power White to ground Blue to 7-way at rear of vehicle Red to cold side of the stop light switch The cold side of the stop light switch will have power only when the brake pedal is pressed. The red wire carries the signal from the brake pedal to the controller so it can send a signal on the blue wire to the trailer's brakes. The wiring harness to hardwire into your 1999...
    view full answer...
  • Brake Controller Wiring Harness for Curt Discovery in 2017 Chevrolet Colorado
    Brake controllers are not vehicle specific technically so the Curt Discovery # C51120 will work in your 2017 Chevrolet Colorado. The reason we include them on our fit guide is because of the custom harnesses that may or may not be available. Since your truck isn't listed as of yet it's likely because Curt hasn't had a chance to test fit your truck since it's brand new and nothing has been officially confirmed. With that being said, if you have the wiring under the dash in your truck...
    view full answer...
  • No Power To Curt Venturer Brake Controller On 2001 Jeep Grand Cherokee
    You stated that you have your controller all hooked up to your 2001 Jeep Grand Cherokee. It sounds like the power wire has possibly not been connected. When properly installed, the brake controller will still turn on. For you model Jeep, we offer a harness that connects to the back of the brake controller, part # C51110. The harness number is part # C51515. The plug connects to the back of the brake controller, and the 4 wires on the other end are hardwired to your vehicle. The black...
    view full answer...
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  • Brake Controller Recommendation and Installation for a 2009 Chevy Silverado
    On your 2009 Chevy Silverado there are 4 blunt cut wires under the dash that are to be used to install a brake controller like the Curt Triflex part # C51140 that you referenced. You will need the universal install harness # C51515 to go along with this controller. For more information on how to install a brake controller in your vehicle check out the install video and help article I attached.
    view full answer...

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