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Curt Spectrum Trailer Brake Controller - Dash Mounted Knob - Up to 4 Axles - Proportional
Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In

Part Numbers: C51170,C51458

$278.30
Trailer Brake Controller

In Stock
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Curt Spectrum Trailer Brake Controller - Dash Mounted Knob - Up to 4 Axles - Proportional
part number: C51170

You can stick the control knob to the dashboard, plug in the module, and your brake controller installation is done with no drilling and no hardwiring. The knob is large and easy to use, while the main unit is out of sight behind the dash.

Features:

  • Proportional braking - Smooth, safe, and good for your brakes long-term
  • Fingertip control
    • Adjust braking output and sensitivity by turning the dial
    • Push the button to activate manual override
    • Troubleshoot with colored LED indicators
  • No-drill installation - Knob adheres to dash, main unit installs behind it
  • Assembled in the USA


Specs:

  • Application: trailers with up to 4 axles (8 brake assemblies)
    • Compatible with electric or electric-over-hydraulic trailer brakes
    • Compatible with ABS brakes, cruise control, low-voltage wiring, multiplex wiring, and PWM systems
  • Main unit dimensions: 3" long x 3-1/2" wide x 7/8" tall
  • Control knob dimensions:
    • Extension: 1-1/2"
    • Diameter: 1-3/4"
  • Cable length: 4'
  • Warranty:
    • Limited lifetime on brake controller
    • Limited 1-year on wiring harness


How Does the Curt Spectrum Work?

The Spectrum puts control of your trailer's brakes at your fingertips and, with bright LED indicators, you know what your brake controller is doing at a glance.


Curt Spectrum Dash-Mounted Knob

You can adjust all of your settings using the control knob. To switch between modes, press the control button in the center of the knob. Each mode has its own distinct LED display with several different colors and patterns to eliminate any guesswork as you cycle through.


Curt Spectrum LED diagnostics

Output: Braking output 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 set the braking output as high as you can without locking up the brakes.


Sensitivity: This controls the aggressiveness of your trailer's braking, meaning how quickly the brakes reach the set output level. This is a great adjustment to make when you're towing a heavy load and the trailer will need more umph to bring it to a stop so it doesn't push your vehicle forward. If your vehicle takes too long to come to a stop, increase the setting. If it stops too abruptly, lower the setting. You may also need to adjust the sensitivity based on your own preferences, or when the trailer load or road conditions change.


Manual Override: The Curt Spectrum keeps the manual override within easy reach. The manual override functions as time-based for a slow reduction in trailer braking, great for stopping sway or controlling your trailer's momentum in an emergency. To engage the manual override, just press and hold the button on the control knob. This will activate the trailer's brakes and brake lights without you having to apply the brakes on your tow vehicle, perfect for limiting trailer movement while you're cruising.


Curt Spectrum review

No-Drill Installation

The Curt Spectrum comes in 2 pieces: the main unit and the control knob. Because the only part that you need to be able to access is the control knob, the main unit can be mounted out of sight and out of the way. You don't have to worry about banging your knee on a bulky brake controller or interfering with your vehicle's lower airbags.


Curt Spectrum Dash Knob

The dash-mounted control knob can be installed in any convenient spot that's easy for you to see and reach. This can be a blank switch panel, an open spot on your center console, or wherever there's space on your dashboard. The knob sits flush against the dash, so you don't have to worry about finding enough clearance behind the dash. You can use either the included screw to mount the knob, or the adhesive pad for a drill-free installation.


Once you've decided where you want to put the control knob, you'll need to find a good place to install the main unit. Your only restriction is the 4' plug-in cable that has to be able to reach between the main unit and the control knob. Thanks to the 3-axis accelerometer, the main unit can be positioned at any angle or position. No matter how you install it, the unit will sense the direction of travel and its orientation.


If your vehicle already has a plug-in brake controller wiring harness, just connect the main control module 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.


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.


Note: If a custom brake control wiring adapter is not available for your vehicle, a 30-amp circuit breaker (sold separately) may be required for installation.


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 Spectrum 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 ensure that your trailer slows at the same rate. The result is uniform braking across your towing setup. No push-pull action - just smooth, proportional braking every time.



51170 Curt Spectrum Trailer Brake Controller - Dash Mounted Knob - Proportional - 1 to 4 Axles

Item # C51170

California residents: click here



Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In
part number: C51458

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 behind 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 connectors plug into the built-in port underneath 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 connector underneath your vehicle's dashboard, located to the right of your steering wheel.


No hardwiring is required to install this adapter. After you plug it into your vehicle's connector, 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.



51458 Curt Quick Plug Brake Control Adaptor Harness

Replaces 51439

California residents: click here




Customer Satisfaction Score:

Ratings & Reviews

4.6

498 reviews
You can stick the control knob to the dashboard, plug in the module, and your brake controller installation is done with no drilling and no hardwiring. The knob is large and easy to use, while the main unit is out of sight behind the dash. 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 behind your vehicle's dash.

by: Michael06/16/2025



by: Bt06/07/2025



by: Philip 12/18/2024



by: tom 02/21/2025



by: Nancy 02/19/2025



by: Brian 01/05/2025



by: David 03/03/2025



by: Sam04/02/2025



by: Joshua03/22/2025



by: Steven04/21/2025



by: Chris 01/14/2025



by: Justin 01/28/2025



by: Joshua03/14/2025



by: Jason05/14/2025



by: Eddy 10/02/2024

Martha was excellent to work with!



by: Tino08/06/2024

A wonderful customer experience. Worked with professionals who guided me in selecting the correct product. Thank You!



by: Steven S09/24/2024

Brittany was professional and patient not to mention helpful.



by: Randall 12/05/2024

Excellent service



by: Eric 11/18/2024

Great shopping experience and quick del ivery.



by: Douglas 02/18/2025

Only ised a short time and it worked as advertised.



by: Jesse03/11/2025

Small form factor works great



by: Jarred08/25/2024

Installation was easy, really liked the tape option to try out different placements before drilling for a permanent mount.



by: Frank03/29/2025

Extremely easy to install. Works great!



by: Roy09/29/2024

Install was a breeze because of the vehicle specific pigtail, etrailer's customer service is excellent and the information on installation helped me locate my plug



by: William04/11/2025

They were very helpful on the phone to make sure i purchased the correct setup for my truck. I received it that week and installed it over the weekend. So far it is out performing the previous brake that was installed.


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Ask the Experts about this Trailer Brake Controller


  • Troubleshooting Curt Spectrum Brake Controller - No Lights On Control Knob
  • The Curt Spectrum Brake Controller # C51170 should illuminate, even if the trailer is not connected. If you are getting no lights at all, this likely means the control unit is mis wired, or there is contamination in the trailer plug socket. We recommend double checking your wiring and making sure everything is done correctly. Also clean and dry your trailer plug. I have included Curts troubleshooting guide below.
    view full answer...

  • Troubleshooting Installation of Curt Spectrum Brake Controller on 2011 Toyota Sienna
  • The calibration process of the Curt Spectrum # C51170 should only happen after initial installation and should be run before you plug in the trailer to your tow vehicle. You should have seen the green lights on the knob light up in a clockwise motion 7 times, which indicates the calibration is occurring. If you've gone through this process and the error occurred, then the lights on the knob can tell you a bit about what's potentially going on. If you're seeing all red lights that would
    view full answer...

  • What Lights On Curt Spectrum Are Supposed to Activate When Pressing Brake Pedal and No Trailer?
  • I have added a link near the bottom of this page with the instructions for the Curt Spectrum Trailer Brake Controller # C51170. When not connected to a trailer and pressing on the brakes you should see 2 blue lights flash on each side of the control knob. If you can tell me what you are seeing I can help you to determine what fault you may be having.
    view full answer...

  • How Does Brake Controller Unplug from Vehicle to Prevent Battery Draw
  • Hey Joe, while I don't know what brake controller you have you should be able to unplug it from the back of the brake controller and that would accomplish what you are wanting. What brake controller do you have?
    view full answer...

  • What Colors Will Curt Spectrum Brake Controller Light Up with Brake Pedal Pressed
  • The Curt Spectrum # C51170 will light up from green to red (with the trailer connected) depending on what power setting you chose. This will be the case whether you are parked or heading down the road. I confirmed this with my contact at Curt. I've also attached a photo showing what the display will look like as well as a review video you can check out.
    view full answer...

  • Curt Brake Controller Plug for a 2020 Ford Explorer
  • Yes, the Curt Custom Wiring Adapter for Trailer Brake Controllers part # C51322 will allow you to use a Curt brake controller like the Curt Spectrum Trailer Brake Controller part # C51170 on a 2020 Ford Explorer (All Models). I checked with Curt just to confirm that the Curt Custom Wiring Adapter for Trailer Brake Controllers is indeed correct for a 2020 Ford Explorer so you can be confident this is the correct harness. The plug will be located under the driver dash, near the center
    view full answer...

  • Single Red LED Lights Up When Brakes Pressed on Curt Spectrum Trailer Brake Controller
  • What you have is in fact the Curt Spectrum Trailer Brake Controller # C51170. The single red light means it is working properly. More lights will light up as more brake power is asserted. This all depends on the settings of the brake controller. If you haven't changed any settings yet I recommend starting on page 11 of the manual to get it properly setup and adjusted. I have attached the link to the instructions below.
    view full answer...

  • Recommended Brake Controller for a 2018 Thor Ace Motorhome
  • For your 2018 Thor Ace Motorhome, I recommend using the Curt Spectrum Trailer Brake Controller part # C51170. The reason for this is because this unit is composed of two main parts, the control box and the output knob. The control box gets mounted out of site and then the output knob will get installed up on your dash for easy use and a very aesthetically pleasing look. The color output of the knob also helps with ease of use. Since your motorhome is on a Ford F-53 chassis, you can use
    view full answer...

  • Comparing the Curt Spectrum Brake Controller to Redarc Tow-Pro Elite
  • By all accounts the Curt Spectrum Trailer Brake Controller # C51170 works well and is easy to use and install on most vehicles. It is a brand new item so not a lot of feedback has come in on it. I did learn a few things though after speaking with our install team about this controller. First, compared to the Redarc controller # RED44FR, the Curt Spectrum is easier to install. It can be surface mounted meaning that drilling is not necessarily required (depends on how you run the wiring).
    view full answer...

  • Troubleshooting Curt Spectrum Output and Sensitivity Adjustment
  • It sounds like the sensitivity needs to be adjusted on your Curt Spectrum # C51170 since it is too aggressive leading to the jumpy stop. To adjust the output and sensitivity you want to follow the instructions. This means you only make adjustments while stopped, with the transmission in park or neutral, parking brake applied, foot off the brake pedal, and no manual control actuation. Adjust the sensitivity by pressing the rotary knob until the brake control is in the sensitivity control
    view full answer...

  • Troubleshooting a Curt Spectrum That Does not Go Through Calibration Sequence
  • There could be a couple of reasons why your Curt Spectrum # C51170 is not calibrating, but it's likely due to your wiring. Even though you're using a plug in adapter # C51523, there still can be an issue with your vehicle wiring. I recommend physically checking your grounds, to make sure that it's to a clean secure surface. If your grounds are good, then check the white and black wires on the main module and make sure they're not flipped; If they are flip them and check again. I also
    view full answer...

  • Does Curt TriFlex Plug Into 2007 Chevy TrailBlazer
  • Even if your 2007 Chevy TrailBlazer has a factory 7-way there is not a plug underneath the dash for a trailer brake controller such as the Curt Spectrum # C51170; you will need to hardwire it with Wiring Adapter # C51515 though the wires will already be run if you have the factory 7-way (you should already have a factory 4-way). If you do not have the factory 7-way you will need to add the Universal Installation Kit for Trailer Brake Controllers # ETBC7. I've added a link on installation
    view full answer...

  • Troubleshooting Brake Lights Always on After Installing a Brake Controller
  • Hey Honori, welcome back. The red wire being the wrong one would cause that issue if it was wired incorrectly but it would also leave your trailer brakes activated. I don't think it's that. It sounds to me like you have a short or fault somewhere in your tow wiring. Did you have any issues with your trailer lights before you installed the brake controller? If you don't know do you have another vehicle you can connect your trailer to? Isolating the problem to the trailer or vehicle is
    view full answer...

  • Troubleshooting Red Light On Curt Spectrum With Trailer Brakes Not Working On a 2014 Toyota Tacoma
  • The first place I would start is with the Curt Custom Wiring Adapter # C51362 that you have connected between the Curt Spectrum Trailer Brake Controller # C51170 and your 2014 Toyota Tacoma. The red light that you are getting when the brakes are pressed indicates that the red wire that connects to the brake switch is either connected to the ground side of the switch or there is a short to ground. I do believe that you have a ground wire issue. The Tekonsha Plug-In Wiring Adapter 3040-P
    view full answer...

  • What Should Display of Curt Spectrum Show When Not Connected to Trailer
  • Hey Paul, with the Curt Spectrum part # C51170 you should have blue lights on the sides of the display flashing when a trailer isn't connected and then the same lights go solid when the brakes are applied.
    view full answer...

  • Curt Spectrum - What Do Two Flashing Blue Lights Mean?
  • Hello Trent, thanks for getting in touch. The two blue lights on the Curt Spectrum # C51170 knob mean the trailer is disconnected. The lights should flash blue when the trailer is disconnected or they will be steady blue with the brakes are pressed with no trailer connected. The green lights when towing are also normal. The knob will show green/red depending on your braking power setting. I have included the list of the LED color patterns for the knob below. If there is an issue you are
    view full answer...

  • Easy to Install Brake Controller Recommendation for 2009 Ford F-750
  • I have a really easy to use Curt brake controller solution for your 2009 Ford F-750 but we don't have any plug and play solutions like you are wanting. Instead though we have the Curt Echo Mobile part # C51180 which basically just plugs into an active 7-way and once synced to a smart phone is ready to tow. It's also a proportional brake controller which means it senses how hard you are applying the vehicle brakes and applies a proportional amount of braking pressure.
    view full answer...

  • Comparing Redarc Liberty and Curt Spectrum Brake Controllers For a 2023 GMC Sierra 1500
  • Personally, I have seen a lot fewer issues with the Redarc Tow-Pro Liberty # RED24FR than with the Curt Spectrum # C51170. The Spectrum was released in early 2018. Currently Redarc only offers the one size control knob. To install the Redarc Liberty # RED24FR in your 2023 GMC Sierra 1500 you will need the Tekonsha Pigtail # 3064-P and the Redarc to Tekonsha Adapter # 331-TPH-017. This will support up to 2 braking axles or 4 brake assemblies. If you go with the Curt Spectrum # C51170
    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
    view full answer...

  • 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...

  • Tekonsha Brake Controller Adapter for 2020 Ram 1500 With Factory 7-Way
  • The Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In # C51458 is absolutely compatible with your 2020 Ram 1500 with the factory 7-way.
    view full answer...

  • Which Curt Brake Controller Harness Fits a 2015 Ram
  • Part of the problem is the harness you are using is the incorrect one. You would need the part # C51458 for your 2015 Ram 1500 and not the # C51453. The correct harness for your does not have the extra wire that you are mentioning since your truck does not require it.
    view full answer...

  • Wiring Harness to Install Tekonsha Brake Controller on 2022 Ram 1500
  • To install a Tekonsha brake controller on your 2022 Ram 1500 you will just need the Wiring Adapter # C51458. The gray plug will connect to your vehicle under the dash and then you'll cut off the black connector and splice it (per color) to your current Tekonsha pigtail. If you plan on still using the brake controller with your old truck when you need to then you might consider picking up another mounting bracket for your Ram. For example, the Prodigy P3 # 90195 would use the mounting bracket
    view full answer...

  • Does Curt Assure Trailer Brake Controller Plug Into 2019 Ram 2500
  • The Curt Assure is 100 percent compatible and will work with your 2019 Ram 2500. You only need the Plug-In Wiring Adapter and you're set. This is a great choice for a brake controller because it is simple to use, has a really nice, easy-to-read display and will give you consistently smooth braking. There are no other items you need except the brake controller and harness; the exact part numbers you need are the following: - Curt Assure Trailer Brake Controller # C49UR - Curt Custom
    view full answer...

  • Does Curt Assure Trailer Brake Controller Work With 2019 Ram 1500 Classic
  • So long as your 2019 Ram 1500 Classic does NOT have the factory brake controller, then yes, you can use the Curt brake controller, and you will also need the correct wiring harness, which I've listed below for you: - Curt Assure Trailer Brake Controller with Dynamic Screen # C49UR - Curt Custom Wiring Adapter for Trailer Brake Controllers # C51458 The Assure is a superb option for a brake controller because it not only gives your trailer smooth braking proportional to that of your
    view full answer...

  • Brake Controller Install Harness Recommendation for 2018 Jeep Wrangler
  • Yes, I confirmed with Curt that the trailer wiring install harness part # C51458 that you referenced is a confirmed fit for your 2018 Jeep Wrangler and will make installing a brake controller easy. It will plug right into the port under the dash of your vehicle to make installing the brake controller easy.
    view full answer...

  • Does Curt Discovery Brake Controller in 2018 Ram 1500 Require Going to Dealer
  • Nope, you do not have to go to the dealer at all in order to install the Curt brake controller in your 2018 Ram 1500. All you need is the brake controller and the plug-in adapter, which are the following for your truck: - Curt Discovery Trailer Brake Controller # C84VV - Curt Custom Wiring Adapter for Trailer Brake Controllers # C51458
    view full answer...

  • Does Curt Brake Controller Harness Fit New Body Style 2020 Ram 1500
  • Yes I can; the Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In # C51458 is a fit for the new body style 2020 Ram 1500.
    view full answer...

  • Can Curt Discovery NEXT Brake Controller Install in 2018 Ram 1500
  • So long as you do NOT have the factory brake controller your 2018 Ram 1500 can install the Curt Discovery NEXT Trailer Brake Controller # C84VV with the Wiring Adapter for Trailer Brake Controllers - Dual Plug In # C51458.
    view full answer...

  • Curt Brake Controller Install Harness for 2017 Ram 2500
  • For your 2017 Ram 2500 the correct Curt brake controller install harness is the # C51458 which will work great with most of the Curt controllers but not the Discovery as this controller does not like the lower voltage that your truck puts out for the brake signal. You would have to go with a new controller like the Venturer part # C74VV.
    view full answer...

  • Is There An Adapter Available For Red Arc Tow-Pro Brake Controller For 2019 Jeep Wrangler
  • Yes, you can use the Curt Adapter part # C51458 for the 2019 Jeep Wrangler Rubicon with the Redarc Tow-Pro Elite part # RED44FR. You would just need to cut off the end of the adapter that goes into the brake controller and hard wire it to the Red Arc controller. The other end would plug into the factory tow port.
    view full answer...

  • Brake Controller Pigtail Needed For a 2023 Ram 1500
  • Kerry, you are going to need to select the correct pigtail for your brake controller based on what controller you have. We have the Curt Pigtail # C51458 for a Curt Brake Controller # C24VV or the Tekonsha Pigtail # 3024-P for a Tekonsha Brake Controller # 90195.
    view full answer...

Info for these parts were:

Employee Lindsey S
Edited by:
Lindsey S
Employee Jameson C
Expert Research:
Jameson C
Employee Cole B
Installed by:
Cole B
Employee Chelsea B
Written by:
Chelsea B
Employee Wilson B
Updated by:
Wilson B
Employee Kristina F
Updated by:
Kristina F
Employee Isabelle B
Updated by:
Isabelle B

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