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Curt TriFlex NEXT Trailer Brake Controller - 1 to 4 Axles - Proportional
Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In

Part Numbers: C24VV,C51525

$148.89
Retail:$206.75
You Save: $57.86
Trailer Brake Controller

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Curt TriFlex NEXT Trailer Brake Controller - 1 to 4 Axles - Proportional
part number: C24VV

This compact brake controller fits nicely in your cab. It's designed to mount flush to the dash and is only 1" thick. The controls are simple, the LED display is large and bright, and the manual override is easy to reach in a pinch.

Features:

  • Activates trailer brakes in proportion to your vehicle's braking
    • Automatically adjusts trailer's braking based on deceleration of tow vehicle
    • Automatically increases power when going downhill and decreases when going uphill
  • Shows you braking and sensitivity settings and error codes on a simple LED display
  • Uses rocker switches to set settings
  • Activates manual override with pinch-trigger
  • Protects your vehicle, trailer, and controller
    • Runs continuous diagnostic checks
    • Minimizes drain on car battery with sleep mode
    • Keeps trailer brakes from overheating by reducing power output during prolonged stops
    • Defends brake controller and trailer breakaway systems against shorts
    • Prevents positive and negative power reversal with built-in polarity protection
  • Mounts at any angle
    • Automatic leveling
    • Mounting bracket and hardware included
    • Plug-in, vehicle-specific brake control adapter (sold separately) available for certain vehicles


Specs:

  • Application: trailers with up to 4 axles (8 brake assemblies)
    • Compatible with electric trailer brakes
    • Compatible with ABS brakes, cruise control, low-voltage wiring, multiplex wiring, and PWM systems
  • Dimensions: 4" long x 3-1/8" wide x 1" tall
  • Limited lifetime warranty


Gain and Load Adjustment

Curt TriFlex NEXT

Gain is the maximum amount of power that will be applied to your trailer's brakes. How much braking output you need is determined by the weight of your trailer; a heavier trailer will need more power to bring it to a stop. You want to go as high as you can without the trailer brakes locking up. Use the gray rocker switch to adjust the gain on a scale of 0.5 to 9.9 in increments of 0.5.


Once you have the gain set, you can fine-tune your braking by adjusting the load control on a scale of 1 to 9 using the black rocker switch. This controls the aggressiveness of your trailer's braking, meaning how quickly the brakes reach the maximum braking level. If your vehicle takes too long to come to a stop, increase the setting. If it stops too abruptly, decrease the setting.


LED Display

The LED display on the TriFlex is large and easy to read at a glance. You can adjust the brightness or trigger night mode so it won't glare obnoxiously on your dash. It also will give you error messages you can use to troubleshoot.


Curt Discovery NEXT troubleshoot

Safety Features

The TriFlex offers key safety features to prevent damage to various components of your towing setup. This starts with built-in protection against shorts and positive and negative power reversal, as well as continous diagnostic checks to alert you to any potential problems as they come up. To minimize the drain on your vehicle's battery, the TriFlex will automatically go into sleep mode after 5 minutes of inactivity. Sleep mode will turn off again the moment you press the brake pedal.


Installation

Automatic leveling means your mounting options are limitless, so long as you can still easily access the controller and the manual override. The included bracket is designed to mount the brake controller flush to the dash so it takes up almost no space at all.


If your vehicle already has a plug-in brake controller wiring harness, just connect the unit to it. Otherwise, you will need to purchase a vehicle-specific wiring harness (sold separately) to plug into. If a harness is unavailable for your vehicle, hardwiring will be necessary.


Note: If a custom brake control wiring adapter is not available for your vehicle, one of the following will be required:

20-Amp circuit breaker (9506P - sold separately) for 2- to 4-brake applications

30-Amp circuit breaker (38630 - sold separately) for 6- to 8-brake applications


If you don't already have a 7-way plug at the back of your vehicle, take a look at our exclusive 7- and 4-way brake control installation kit (ETBC7 - sold separately).


What is Proportional Braking?

What is proportional Braking

Proportional braking means that your trailer brakes mimic your tow vehicle's brakes. If you slam on the brakes in your vehicle, your trailer brakes will activate with the same intensity; if you brake lightly, your trailer brakes lightly too. The trailer's braking is in proportion to your vehicle's braking. This saves wear and tear on the tires and the brakes on both your vehicle and trailer.


The TriFlex uses an internal 3-axis accelerometer to sense how your vehicle is braking so it can send the right amount of braking power to your trailer. It measures the inertia of your tow vehicle and activates the trailer's brakes to slow at the same rate. The result is uniform braking across your towing setup. No push-pull action - just smooth, proportional braking every time.



51146 Curt Tri-Flex NEXT Proportional Trailer Brake Control

Replaces Curt 51140

California residents: click here



Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In
part number: C51525

Install your Curt electric trailer brake controller quickly and easily with this custom wiring adapter. Simply plug one end of the adapter into your brake controller and then plug the other end into the built-in port beneath your vehicle's dash.

Features:

  • Plug-in wiring adapter allows for quick, simple installation of your electric trailer brake controller
  • No cutting or splicing required
    • Custom connector end plugs into the built-in port beneath the dash of your vehicle
    • Other end plugs into the back of your electric brake controller
  • Compatible with time-delayed and proportional brake controllers from Curt
    • Brake controller must have built-in plug for adapter to connect - will not work on controllers with pigtail wiring harnesses
  • 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. When this is done, a port is installed at your dash so that you can easily plug in a brake controller.


This adapter plugs into the port on your vehicle's built-in brake control wiring harness. The harness is located underneath the dash, to the left of the steering column, and it is taped to another harness near the emergency brake pedal.


No hardwiring is required to install this adapter. After you plug it into the factory port, you simply plug the other end of the adapter directly into your electric trailer brake controller. Because there are no wires to connect, installation is not permanent. You can unplug and remove your brake controller at any time to transfer it to another vehicle or securely stow it away.



51525 Curt Quick Plug Brake Control Adaptor Harness

California residents: click here




Customer Satisfaction Score:

Ratings & Reviews

4.7

981 reviews
5 Stars
(1602)
4 Stars
(226)
3 Stars
(52)
2 Stars
(20)
1 Star
(62)
This compact brake controller fits nicely in your cab. It's designed to mount flush to the dash and is only 1" thick. The controls are simple, the LED display is large and bright, and the manual override is easy to reach in a pinch. Install your Curt electric trailer brake controller quickly and easily with this custom wiring adapter. Simply plug one end of the adapter into your brake controller and then plug the other end into the built-in port beneath your vehicle's dash.

by: Ronald11/13/2025



by: Mark11/13/2025



by: Corey 08/11/2023



by: Brian 07/25/2023



by: Brad 11/20/2021



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by: Ronald 10/20/2023



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by: Jamie 06/26/2021



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by: Brian 07/14/2021



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by: Jack 03/13/2021



by: Carol 10/12/2023



by: Stephen 07/30/2022



by: Kris 07/02/2023



by: Robert 08/12/2021


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


  • How Does Curt TriFlex NEXT Brake Controller Mount
  • You're right, the mounting bracket is unique (in a good way) for the Curt TriFlex NEXT Trailer Brake Controller # C24VV. The bracket is smaller and all you do is put the included adhesive tape on the bracket and stick it wherever you like under your dash. Screws are also included and you can use them with the adhesive to mount the bracket under your dash. Then you'll simply slide in the TriFlex NEXT controller and that's it. This type of bracket takes up less space than the normal
    view full answer...

  • Troubleshooting Curt Triflex Brake Controller Showing OL Code on Display
  • The Curt Triflex brake controller is known to have more problems than other brake controllers so I would not rule out the problem being the controller. Testing the brake controller is fairly easy. Sever the blue brake output wire near the brake controller leaving enough room to reconnect it and then apply the manual slide. Using a circuit tester like the Quickee Tester, part # PTW2993, you should get output to the controller side of the wire you severed. If the manual slide activates
    view full answer...

  • Brake Controller Installation on my 2017 Audi Q7
  • With the Curt Triflex part # C24VV and the Curt Adapter part # C51522 you will have all you need to successfully install your controller. I have linked a video for you showing the operation of the controller. Check it out to familiarize yourself with it.
    view full answer...

  • How to Reset Curt Triflex Brake Controller
  • Try unplugging the brake controller for 10 seconds or so and then replugging it in. Sometimes brake controllers like the part # C24VV just need to be reset and this is the corret way to do that.
    view full answer...

  • Recommended Weight Distribution System for a Keystone Springdale Mini RV
  • Hey Jacobus glad you asked your question and congrats on the new RV! You are going to be way overrated if you use a 1,500 lbs or 1,000 lbs tongue weight rated weight distribution system. Bigger in this situation is definitely not going to be better. If you run that high of a capacity system you'll have an extremely ridged and uncomfortable ride. Plus there's potential to damage your trailer's frame. For your Keystone Springdale Mini RV, I recommend the Equal-i-zer Weight Distribution
    view full answer...

  • Troubleshooting Curt Brake Controller that Rests When Brakes are Released
  • So the controller resets every time you apply and release the brakes? You might check to make sure you made all the connections correctly when you wired it to the correct functions. Most likely it sounds like there's an issue with the red and black wires of the controller. The black wire of the controller needs to run to a power source that is hot all the time and the red wire needs to run to the stoplight circuit. Now all of that said the TriFlex is known to be prone to internal problems
    view full answer...

  • Troubleshooting Brake Controller with OL Code when Brakes are Applied
  • If you check out the attached instructions for the Curt TriFlex Trailer Brake Controller # C24VV you can see that the OL code you are getting means that there is an "Overloaded output circuit, trailer brake system fault". Whichever controller you have the problem and solution is the same. You have a short on your brake signal circuit from your brake controller to your trailer brakes which is causing too much power draw. Check both the tow vehicle and trailer connectors and make sure
    view full answer...

  • LED Display of Curt TriFlex # C24VV Brake Controller Remains Illuminated When Vehicle is Shut Off
  • Because it's connected to a constant 12-volt power source, the LED you mention will remain illuminated after the vehicle is shut off. This is normal, and does not indicate a problem of any kind. After 15 or so minutes of inactivity, the brake controller goes into a 'sleep' mode, and will reactivate next time the brake pedal is pressed. The LED only draws a few milliamps of power, which would only drain the battery if the vehicle sat unused for months. You could certainly unplug the controller
    view full answer...

  • Will Curt Triflex Brake Controller Cause Battery Drain
  • Hey Christa, so the Curt Triflex part # C24VV shouldn't be draining your battery since it should be going into a sleep mode when not in use. To cut power to it you would need to unplug it at the rear of the controller. There isn't a master power switch for it as that would cause it to lose settings.
    view full answer...

  • Troubleshooting "Short" Error Message On Curt TriFlex NEXT C24VV
  • Hello Kevin, thanks for reaching out. It sounds like you have already done the most helpful troubleshooting step by hooking up another controller and verifying that everything works fine. This eliminates the trailer wiring as a potential cause of the issue and it also eliminates the truck as a culprit as well. That really leaves us with the controller as the cause of the issue, more specifically an internal short. You can try cutting the blue wire coming from the controller at least 6"
    view full answer...

  • Troubleshooting Curt Triflex Brake Controller that Flashes that a Trailer is Connected
  • The Triflex # C24VV sometimes does need to be reset occasionally. Try unplugging it and plugging it back in after a few seconds and it should work again. Otherwise you have a short between the black wire and the red wire and your controller therefore is thinking you have the brakes all the time. If you can check the connections between the two circuits there might be exposed wire between the two and that's why you are seeing the issue. I also attached a help article on troubleshooting
    view full answer...

  • Will Curt TriFlex NEXT Controller and Wiring Adapter Fit a 2022 Genesis GV70?
  • Hey Anthony, thanks for reaching out! The Curt TriFlex NEXT Trailer Brake Controller #C24VV and Curt Adapter # C77BR will fit your 2022 Genesis GV70 just fine. The only way a Tekonsha adapter will work is if you cut off the connector for the controller side and splice it into the wiring for the brake controller. So, while the adapter might cost a little less, it kind of defeats the purpose of the plug-in adapter anyways so it would be better just to use the Curt adapter. Do you already
    view full answer...

  • Curt C24VV Brake Controller Troubleshooting Reading Voltage Numbers without Trailer
  • Most likely it's just corrosion on the trailer wiring connector confusing your TriFlex part # C24VV into thinking that a trailer is connected so first try cleaning that. If not this controller is prone to internal bugs so you might try unplugging it and plugging it back in to reset it.
    view full answer...

  • Troubleshooting Curt TriFlex Brake Controller that Flashes 1.0 With No Trailer Connection
  • This is a common issue when there is corrosion built up on the brake output pin of the 7-way. What this does is cause the controller to sense a slight amperage draw which confuses it into thinking a trailer is connected. The other thing you can try is unplugging the controller and plugging it back in. Sometimes the Curt controllers just need to have a hard reset to function normally.
    view full answer...

  • What Problems Does the Curt Triflex Brake Controller Have with 7-Ways With LED Test Lights
  • What happens is that the load that LED puts on the brake output circuit tricks the brake controller into thinking that there is a trailer connected and the brake controller will start activating regardless if there is a trailer connected or not. Technically it would work just fine with a trailer, its just that it will always activate regardless if there is a trailer back there or not. I attached installation instructions and an install video for you to check out also.
    view full answer...

  • Parts Needed to Install a Trailer Brake Controller on a 2009 Audi Q7
  • If your 2009 Audi Q7 does not have a factory trailer connector at the rear of the vehicle then you will need to install both the ZCI Circuit Protected Vehicle Wiring Harness w/ 4-Pole Flat Trailer Connector and Installation Kit part # 119250KIT and the Universal Installation Kit for Trailer Brake Controller part # ETBC7 in order for a brake controller to work. Trailer brake controllers are universal and can be adapted to fit any vehicle with the correct wiring harness. The correct wiring
    view full answer...

  • What is Required to Install a Brake Controller in 2019 Toyota Highlander With 4-Way
  • Since you have a 4-way in your 2019 Toyota Highlander you can install a brake controller like the Curt TriFlex Trailer Brake Controller # C24VV with Wiring Adapter # C51515 so long as you use the Universal Installation Kit for Trailer Brake Controller # ETBC7. This has a 7-way to 4-way adapter but that alone isn't enough to install a break controller. This kit also includes the necessary circuit breakers, wire and additional hardware you will need to install a brake controller. I have
    view full answer...

  • Troubleshooting Curt TriFlex Brake Controller Not Showing Activation
  • On your Curt TriFlex Trailer Brake Controller # C24VV, the decimal point as you put it is standby mode with no trailer connected. The blank screen is also standby mode and that screen is what is seen when simply starting the vehicle, but that screen should illuminate when you press the manual override or show the decimal point when you hit the brake pedal only while moving since it is a proportional controller. If it does not operate under those criteria, then you will need to have the
    view full answer...

  • How Would Brake Controller Install in 2021 Chevy Tahoe
  • If that part is available it would be through GM only. But you could also bypass needing a connector and just wire what you have found directly to a brake controller like the Brake EVN part # TK63VR instead. For this controller the black wire is the 12 volt power wire, red is stoplight circuit, blue is brake output, and white is ground.
    view full answer...

  • Where is the Factory Trailer Brake Controller Port On a 2022 Chevrolet Tahoe
  • If your 2022 Chevrolet Tahoe does not have the factory tow package then the plug may not be there. If this is the case you would need to hardwire in a brake controller. If your Tahoe does have the tow package then the plug will be under the dash. The plug will often times be taped together with another harness making it not always apparent that it is the plug you are looking for. You may need to do some searching to find the correct plug. Currently at this time (2/10/2022) the only adapter
    view full answer...

  • Parts Needed To Install Curt Assure Trailer Brake Controller On a 2024 Chevy Silverado 2500
  • The Wiring Adapter # C51525 will allow you to connect the Curt Assure Trailer Brake Controller # C49UR on your 2024 Chevrolet Silverado 2500HD.
    view full answer...

  • Curt Brake Controller Wiring Plug for a 2021 Chevy Silverado 1500
  • Thanks for reaching out, Alan! In order to install a Curt brake controller to your 2021 Chevy Silverado 1500 you'll need the Adapter # C51525, yes. This will connect under the dash to that larger gray connector you found. If you don't already have the brake controller then I really like the Curt TriFlex NEXT Trailer Brake Controller # C24VV as it has a proportional operation so the trailer brakes match the time and intensity of your truck braking.
    view full answer...

Info for these parts were:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Kathleen M
Installed by:
Kathleen M
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B
Employee Ronnie R
Written by:
Ronnie R
Employee Jonathan Y
Video by:
Jonathan Y
Employee Matthew B
Test Fit:
Matthew B

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