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  1. Trailer Brake Controller
  2. CURT
  3. Electric
  4. Electric over Hydraulic
  5. Time Delayed Controller
  6. Up to 4 Axles
Curt Discovery NEXT Trailer Brake Controller - Up to 4 Axles - Time Delayed
CURT

Curt Discovery NEXT Trailer Brake Controller - Up to 4 Axles - Time Delayed

$99.95
Retail:$134.11
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Trailer Brake Controller
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In Use/Installed

This compact brake controller fits nicely in your cab. You can mount it anywhere you like and it's only 1" thick. The LED display is large and bright so it's easy to see, while the large manual override is easy to reach in a pinch. Great Prices for the best trailer brake controller from CURT. Curt Discovery NEXT Trailer Brake Controller - Up to 4 Axles - Time Delayed part number C84VV can be ordered online at etrailer.com or call 1-800-940-8924 for expert service.
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  • Reviews (43)
  • Q & A (0)
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CURT Trailer Brake Controller

  • Electric
  • Electric over Hydraulic
  • Time Delayed Controller
  • Up to 4 Axles
  • CURT
  • Under-Dash
  • Under-Dash Box
  • Plug-In
  • LCD Display
  • Single Trailer Only

This compact brake controller fits nicely in your cab. You can mount it anywhere you like and it's only 1" thick. The LED display is large and bright so it's easy to see, while the large manual override is easy to reach in a pinch.


Features:

  • Time delayed: activates trailer brakes with preset intensity
  • Rocker switches control gain and load settings
    • Gain: adjusts on scale of 0.5 to 9.9
    • Load: adjusts on scale of 1 to 9
  • Large pinch-trigger manual override
    • Easy to reach without taking your eyes off the road
  • LED display is bright, large, and adjustable
    • Displays error messages so you can troubleshoot
    • Shows settings using numbers and letters
    • Adjusts brightness for best visibility
  • Auto-sleep mode activates after 5 minutes to prevent draining the battery
  • No mounting restrictions: install anywhere at any angle
    • Included mounting bracket and hardware hold the unit flush against the dash
    • Custom plug-in adapter (sold separately) available for select vehicles


Specs:

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


Gain and Load Adjustment

Curt Discovery 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 orange 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 Discovery 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 clear error messages you can use to troubleshoot.


Curt Discovery NEXT troubleshoot

Installation

Because inertia plays no role in the functioning of this controller, your mounting options are limitless, so long as you can still easily access 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, you'll be able to connect the unit right to it. Otherwise, you will need to purchase a vehicle-specific wiring harness (sold separately) or hardwire the included pigtail harness to your vehicle.


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 Time-Delayed Braking?

what is time-delayed braking

Time-delayed braking means that when you apply the brakes in your vehicle, the controller activates the trailer brakes at a pre-set intensity and rate. Both the amount of braking power (gain) and rate of application (load) can be adjusted to suit your preference, the road conditions, the type of trailer, and the weight of your load. To determine which levels are best for your application, test your towing setup and choose what feels right.



51126 Curt Discovery NEXT Time Delay Trailer Brake Control - 1 to 4 Axles

Replaces Curt 51120

Item # C84VV

Installation Details C84VV Installation instructions


California residents: click here


Customer Satisfaction Score:

Ratings & Reviews

4.7

43 reviews
This compact brake controller fits nicely in your cab. You can mount it anywhere you like and it's only 1" thick. The LED display is large and bright so it's easy to see, while the large manual override is easy to reach in a pinch.

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Great product



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Easy ordering, good prices, fast shippi ng.



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Perfect and helpful customer support on the phone! Product arrived VERY QUICKLY and fit perfectly. Will continue to do business with e-trailer!



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Fast shipping and works perfectly



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Haven’t used yet install was a breeze super easy with the plug adapter for my vehicle



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Worked great! 2012 Ram 1500.



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On time and installed effortlessly all was as discussed and would recommend to anyone looking for easy installation.



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easy plug and play



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Every thing was just great. Easy to hook up l had trailer brakes in just a few min. And the wire harness was perfect thank you



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Very easy install with the custom wire harness



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Fast shipping and communicative online purchase! Brake controller comes with harness for your vehicle and just plugs and plays.



by:

Purchased this controller for a 2004 Toyota Tundra Limited and it has preformed perfectly! I haven't had any complaints. It reacts and adjusts quickly. Along with the plug and play function there's not much more I can say. Great product!

Gwendolyn Y. profile picture
Etrailer Expert

Gwendolyn Y.

3/21/2025

Love to hear it, Steve! What are you towing behind your Tundra?



by:

Connected to the OEM plug perfectly, works great on our Sunset 16 ft trailer.

Brooke M. profile picture
Etrailer Expert

Brooke M.

5/15/2025

When are you going on your next trip? Glad it was an easy install :)



by:

I only towed with it once and then I sold the truck I installed it in. I pulled the two axle camper bought 350 miles and it worked fine.



by:

Took about 10 minutes to install. Have not made all the adjustments yet, but is easy to understand.



by:

Tested . Work fine and advertised



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excellent service and delivery.



by:

Like its compact size and simple operat ion.


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Show More Reviews

See what our Experts say about this CURT Trailer Brake Controller

  • Where to Connect the Adapter to Install a Curt Brake Controller in a 2017 Nissan Pathfinder
    To install a Curt Brake Controller, like the Discovery # C84VV, on your 2017 Nissan Pathfinder you will simply need to plug the Custom Wiring Adapter # C51382 under your dash like you mentioned. I am attaching a video where one of our install guys installed a Tekonsha Prodigy P2 # 90885 in a 2013 Pathfinder using the Tekonsha Wiring Adapter # 3050-P. If you skip to the 2:45 mark you can see where he plugs in the adapter for the Prodigy P2. Your Curt adapter will plug into the same place.
    view full answer...
    Image 1 for
  • Troubleshooting a Curt Discovery Brake Controller That Has Jerky Brakes
    Wes, it could be possible that your brakes are jerky after they are warm because you adjusted them while they were cold. So what you can do recommended to warm the brakes by applying the manual lever for a bit while driving at slow speed; once they're warmed you can adjust them properly. Another possibility is that the delay is set too long on the controller. I'd suggest trying to set the delay to activate sooner and see if that fixes it. If all that does not work, then there could...
    view full answer...
  • Curt Discovery Brake Controller Shows OL Error When Trailer is Connected
    It is possible that it is a simple wiring issue that is causing the errors on your Curt Discovery brake controller # C84VV. On your 2010 Chevy Silverado, there is a tow package wire bundle under the dash to wire in a brake controller. The tow package red goes to brake controller black. White goes to white, blue to blue, and the light blue or orange wire on the truck goes to the brake controller red wire. The OL indicates an overload and if all of the connections at the brake controller...
    view full answer...
  • Brake Controller Installation on 2011 Toyota Tundra
    If your 2011 Tundra has the factory tow package, which includes the factory installed 7-way trailer connector on the rear bumper, it will be equipped with the tow package plug under the dash, as shown in the photo I've edited for you. Some models with the factory 4-pole (or 4-pin) trailer connector will also have the plug under the dash, you'll need to look for a white plug located above and to the left of the emergency brake pedal, above the toe kick. Occasionally, the plug will be located...
    view full answer...
  • Why Is Stoplight Circuit Difficult to Find on 2017 Ram 1500 For Installing Brake Controller
    Your generation of Ram truck uses a powernet style of wiring at the brake switch wiring which means the voltage will actually read lower than what a 12 volt circuit tester is going to show. Also if you are trying to hardwire a controller you are going to have issues as we've found that if you don't use a harness designed specifically for your truck's wiring setup you may damage the vehicle. So to install the Curt Discovery part # C84VV you have to use the vehicle specific install harness...
    view full answer...
  • Troubleshooting Flashing 0.0 Error Message on Curt Discovery Brake Controller # C84VV
    The troubleshooting guide included in the instructions for the Curt Discovery Brake Controller # C84VV that you referenced does not include this particular display issue, a flashing 0.0, among the possible display messages. My technical contact at Curt has never seen this particular message displayed on a Discovery brake controller. He suggested that either the display is malfunctioning or the controller is bad. Since your brakes are not engaging when you press the pedal with the trailer...
    view full answer...
  • Parts Needed to Add 7-Way and Brake Controller to 2007 Ford F-150 with 4-Way
    If your trailer does not have brakes all you would need is the part # 37185 as an adapter to convert the 4-way to a 7-way. If you do have trailer brakes you would need the # 3035-P, the # 37185, and a brake controller. For a brake controller I would recommend the Prodigy P2 Brake Controller part # 90885. This is our best selling brake controller because of how well it works and how easy it is to set up. Follow the 4-way trailer connector wires from the trailer connector to the front...
    view full answer...
    Image 1 for Image 2 for
  • Brake Controller For 1993 Dodge Ram Truck
    To add a brake controller to your 1993 Dodge Ram truck, a great option is from Curt: - Curt Discovery NEXT Trailer Brake Controller # C84VV I like the # C84VV because it's a no-frills, easy to use, economical option that'll just get the job done - activating your trailer brakes. There are settings for the amount of braking you want, an LED display that shows the power output, and an auto shut-off. So it's really simple but also effective, and the only other thing you will need is the...
    view full answer...
  • Plug-In Curt Brake Controller Adapter for 2024 Ram 1500 & What Controllers Does it Fit
    For your 2024 Ram 1500, the correct Curt brake controller wiring harness is the Curt Custom Wiring Adapter for Trailer Brake Controllers # C51458. This will give you a simple plug-and-play brake controller wiring harness (keep in mind this will not work if you have the OEM brake controller), and here are the brake controllers that this adapter works with: - Curt Spectrum Trailer Brake Controller # C51170 - Curt TriFlex NEXT Trailer Brake Controller # C24VV - Curt Discovery NEXT Trailer...
    view full answer...
  • What Is The Difference Between Proportional and Time Delayed Trailer Brake Controllers?
    The Curt TriFlex NEXT Trailer Brake Controller # C24VV you are looking at is a proportional controller. This means when you press on the brakes the controller is going to have an inertia sensor which then factors in how quickly the vehicle is stopping and adjusts the amount of power going to the trailer brakes from your original setting. The easiest explanation I can give you is when you lightly press the brakes to slow down this controller will lessen the amount of power sent to the trailer...
    view full answer...
    Image 1 for Image 2 for
  • Does 2019 Ram 1500 Need to be Flashed Using Curt Discovery Brake Controller
    Thank you for your purchase from etrailer of the Curt Discovery Brake Controller # C84VV and Wiring Adapter # C51458, we appreciate it. Your 2019 Ram 1500's computer does not need to be flashed/programmed when using this controller it will be plug and play. The exception is if you are replacing the factory brake controller, as you would then need to do so.
    view full answer...
  • Brake Controller Installation in 2000 Ford F-150 That Had Factory Wiring Removed
    Since your 2000 Ford F-150 came with the wiring under the dash you can install the Curt Discovery # C84VV but I recommend using the Universal Wiring Adapter # C51515 and Butt Connectors # DW05744-5 instead of the Custom Wiring Adapter # C51322. The universal adapter has blunt cut wires that you'll attach per function (see below) while the custom adapter is designed to connect directly to that connector that was cut off from under your dash. Here are the connections you'll make for the...
    view full answer...
  • Troubleshooting Curt Discovery Brake Controller Issues on Ram 1500
    The Curt Discovery Brake Controller # C84VV is a time-delay type that is intended to send out a pre-determined amount of braking power after you have applied the vehicle brakes. The other type that is often preferred is the proportional type that will actually sense the amount of braking force in the tow vehicle and send a proportional amount of braking power to the trailer, without a time delay. Based on the symptoms you described I think the issue could be with the wiring on the trailer....
    view full answer...
    Image 1 for
  • Troubleshooting Trailer Brake Controller that Only Functions When Engine Isnt Running
    That is an interesting problem you are having, but the problem lies somewhere in the wiring of the brake controller/7-way. The only way a brake controller is going to work properly with the key in the ACC position but not when the vehicle is running has to be due to wiring. Check to make sure there are no shorts between the two wires you ran to the rear of the 7-way. It sounds like you ran a wire for the 12 volt accessory circuit and an additional wire for the brake output. You might...
    view full answer...
    Image 1 for
  • Curt Discovery Brake Controller Is Only Showing A Dot When Engaging Manual Override
    The Curt Discovery Trailer Brake Controller, # C84VV, should show only the decimal point dot when the controller is activated and a trailer is not connected. If it shows the dot all the time, the red wire is connected to the wrong side of the stop light switch or the wrong switch completely like the cruise control. If you have only the decimal point when the trailer is connected, the usual cause is that the brake controller does not sense the trailer brakes. This could be due to corrosion...
    view full answer...
  • How to Access Vehicle Brake Light Signal for Trailer Brake Controller Installation
    If your 2005 Toyota Sequoia has a factory-installed 7-way trailer connector you can install the Curt Discovery trailer brake controller # C84VV using only the mating wiring adapter part # C51362. If it does not then the installation will be hardwired. You can gain access to the vehicle brake light signal, which is what triggers the Discovery controller to generate output voltage for the trailer brakes, either by tapping into brake light wiring or by installing a fuse tap in the brake light...
    view full answer...
  • Troubleshooting Flashing Display of the Curt Discovery Brake Controller part # C84VV
    The flashing O.L. message with the Curt Discovery Brake Controller part # C84VV when there is no trailer connected indicates that there is a short somewhere on the brake output circuit. I would check all the connections you made on the blue wire from the controller and then also check the trailer connector at the rear of the vehicle looking for any exposed wire or corrosion and fix as necessary. If it only flashes O.L. when the trailer is connected the problem is the same as above but...
    view full answer...
  • Brake Controller Install Harness Recommendation for Curt Brake Controller in 2009 Chevy Silverado
    To install the Curt brake controller part # C84VV in your 2009 Chevy Silverado requires the install harness part # C51515 but this is a harness with 4 blunt cut wires that you'd need to wire to the blunt wires under the dash of your truck since a plug and play harness isn't available. It's a pretty simple process though. You'd just need blue butt end connectors like the # DW05744-5 and you'd be set. I attached an install video that shows the install on a similar Silverado for you to check...
    view full answer...
  • Brake Controller Wiring Adapter for a 2015 Toyota Tacoma with Factory 7-Way
    No worries, the 5-wire harness will work just fine because the extra connection is for the illumination circuit and it's not needed. The Curt Discovery trailer brake controller # C84VV is a fit for your 2015 Toyota Tacoma and the direct fit pig tail adapter # C51362 you referenced is correct. You will simply plug the adapter # C51362 into your factory brake controller tow port and route the pigtail to the location of your choice so you can connect your brake controller.
    view full answer...
    Image 1 for
  • Comparing Curt TriFlex Trailer Brake Controller To Curt Discovery Trailer Brake Controller.
    The main difference is the Curt TriFlex Trailer Brake Controller # C24VV is a proportional brake controller while the Curt Discovery Trailer Brake Controller # C84VV is a time delay controller. The proportional controller will automatically adjust power sent to your trailer brakes based on how hard you are braking, while the time delay always sends the same force no matter how soft or hard you are braking. Those with time delay controllers will often have to reach down to crank up the...
    view full answer...
  • How to Install Curt Discovery Brake Controller in 2008 Ford F-150 With Factory 7-Way
    The Curt Discovery brake controller part # C84VV that you referenced can easily fit your 2008 Ford F-150 with the factory 7-way by using custom install harness part # C51322. This plugs into the brake controller install port under the dash of your truck and then into the back of the controller and you're set.
    view full answer...
  • Curt Discovery Trailer Brake Controller # C84VV Displays Only a Red Dot After Installation
    If your Curt Discovery Trailer Brake Controller # C84VV displays only a red dot when you do NOT have a trailer connected then this indicates that the controller's red (input signal) wire is connected to the wrong side of the brake light switch. This red wire should connect to the COLD side of the switch that has power only when you press the brake pedal. If your Discovery displays the red dot when you DO have a trailer connected then this usually indicates a problem in the trailer brake...
    view full answer...
  • Which is Better a Time Delayed or Proportional Brake Controller
    Between the two controller I would go with the proportional Curt Triflex part # C51140 over the time delayed Curt Discovery part # C84VV. A time delay controller is so named because there is a delay between the time that you initially apply the brakes in your tow vehicle and the time that the controller reaches maximum power output. Unlike a proportional brake controller, which activates your trailer's brakes based on the deceleration of your tow vehicle, a time-delayed controller sends...
    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 # C84VV 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...


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Do you have a question about this Trailer Brake Controller?


Info for this part was:

Employee Lindsey S
Edited by:
Lindsey S
Employee Chris R
Video Edited:
Chris R
Employee Wilson B
Updated by:
Wilson B
Employee Michael B
Installed by:
Michael B
Employee Aidan B
Installed by:
Aidan B
Employee Charles A
Video by:
Charles A
Employee Amanda K
Written by:
Amanda K
Employee Ian F
Test Fit:
Ian F

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