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

Part Numbers: C51140,C51436


Our Price: $84.00

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Curt Up to 4 Axles Brake Controller - C51140
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Curt TriFlex Trailer Brake Controller - 1 to 4 Axles - Proportional
part number: C51140

Proportional brake controller automatically levels when mounted within a 90-degree vertical range and a 40-degree horizontal range. Includes digital display, 9 sensitivity settings, reverse-polarity protection, and continuous diagnostics.


  • Brake controller activates trailer brakes in proportion to your vehicle's braking action
    • Automatically adjusts trailer's braking based on deceleration of tow vehicle
    • Activates immediately - no pausing like with time-delayed brake controllers
  • Automatic-leveling ability - internal sensor detects deceleration even if controller is not mounted flat
    • Position within 90 degrees up or down and within ±20 degrees side to side
  • 9 Sensitivity settings (boost settings) let you adjust initial braking power and aggressiveness
  • Triple-axis accelerometer is highly responsive, ensuring smooth, uniform stopping action
  • Continuous diagnostic check alerts you to any potential problems
  • Integrated safeguards protect your vehicle, the trailer, and the controller
    • Minimizes drain on car battery by entering power conservation mode after 30 minutes of inactivity
    • Keeps trailer brakes from overheating by reducing power output to them during prolonged stops
    • Defends brake controller and trailer breakaway systems against shorts
    • Prevents positive and negative power reversal with built-in polarity protection
  • Surface-mount technology (SMT) allows for consistent, reliable performance
    • Maximizes power output while producing minimal heat
    • Ensures superior operation in rough road conditions
  • Digital display communicates power and sensitivity settings and error codes
  • Built-in, slide-bar manual override
  • Mounting bracket and hardware included
    • Plug-in, vehicle-specific brake control adapter (sold separately) can be used for certain applications to reduce installation time


  • Application: trailers with up to 4 axles (8 brake assemblies)
    • Designed for use with electric or electric-over-hydraulic trailer brakes
  • Dimensions: 3-1/4" wide x 4" long x 7/8" tall
  • Mounting:
    • 90-Degree vertical plane operating range
    • 40-Degree horizontal plane operating range
  • Limited lifetime warranty

Note: If your vehicle's 7-Way trailer connector has LED test lights built into it, the TriFlex brake controller will not be compatible.

Proportional Braking

With a proportional brake controller, you can get heavy-duty emergency braking, general braking, or slow-to-an-idle braking for your trailer automatically. The intensity with which your trailer brakes are activated and the rate at which they are applied are dependent on the deceleration of your tow vehicle. This means that, unlike time-delay controllers - which send the same amount of preset power to your trailer brakes every time - proportional controllers are able to adapt to every braking situation differently. So, if you slam on the brakes in your truck, your trailer brakes will activate with that same extreme intensity. And if you merely slow down as you approach a red light, your trailer will gradually brake in the same manner. Just set the initial power level, select a sensitivity setting, and you're good to go.

As long as the TriFlex controller is properly mounted as indicated in the instructions, it will sense - via an internal inertia sensor - how your tow vehicle brakes. This triple-axis, inertia-based sensor responds to the deceleration of your tow vehicle as you brake by signaling the controller to send out enough power to your trailer brakes so that they are activated with an intensity that matches. The result is uniform braking across your towing setup. No push-pull action - just smooth, proportional braking every time.

Built-In Controls for Adjustable Power

Curt TriFlex Controls and Components

The above diagram shows the controls and components of the Curt TriFlex trailer brake controller.

  1. Digital display
  2. Thumbwheel power output control
  3. Sensitivity adjustment switch
  4. Slide-bar manual override

Output Control

During the initial setup process, use the thumbwheel on top of the TriFlex to adjust the output. The output control lets you set the maximum amount of power that will be applied to your trailer's brakes. Typically, the output is only readjusted when you experience changing road conditions or if you switch over from a heavy, loaded trailer to a much lighter, empty trailer, or vice versa. To get more power to your brakes, rotate the switch to the right. To decrease the power output, move it to the left. The output setting will appear on the digital display when you press the brake pedal or activate the manual override.

Sensitivity Settings

Once you have the overall power set, you can fine-tune the power output by adjusting the sensitivity of the internal sensor. Use the switch on the side of the TriFlex to achieve your desired degree of intensity.

Move the switch toward you to boost the power output, causing your trailer brakes to activate with more intensity right off the bat. This means that they will also reach maximum braking faster simply because they will start out at that higher intensity. This is particularly beneficial if you are towing a heavy load because the intensity required to stop that load may be far greater than that needed to halt your vehicle. Therefore, sending out more initial power to the trailer brakes - and causing them to reach maximum braking faster - allows you to better control the trailer so that it doesn't push your tow vehicle before coming to a complete stop.

There are 9 sensitivity levels (boost levels), with 1 being the least sensitive. At level 9, the sensitivity of the internal sensor is as high as it can go. When you change the setting, the display on the TriFlex will flash the level before reverting back to showing the power output.

Safety Features

The TriFlex offers advanced safety features to prevent damage to various components of your towing setup. When the TriFlex is not in use, it will be in power-saving mode, reducing the power draw to minimize drain on your vehicle's battery. This power-conservation mode begins after 30 minutes of inactivity and ends the moment your vehicle's brake pedal is pressed.

When you stop at red lights, or any time that your truck and trailer are at a standstill with the brakes applied for a prolonged period of time, the TriFlex will reduce the power output to your trailer's brakes, preventing them from overheating.

If ever there is a time that you need to brake your trailer separately from your tow vehicle, the manual override lever is easily accessible. Pushing this slide engages the brakes on your trailer with either full power or the maximum power allowed by the output level, depending on which setting you select. In addition, when you activate this override, the brake lights on your trailer will illuminate, properly warning those behind you of the braking action of your rig.

Automatic Leveling and Simple Installation

The self-leveling feature of the TriFlex ensures that the brake controller continues to function even as you drive up steep hills or through the mountains. Simply mount it in your cab at a vertical angle that is within 90 degrees, and the controller will level itself automatically. Make sure that the controller is also positioned so that the side-to-side angle is within ±20 degrees.

Installation is a snap. After mounting the TriFlex unit in your cab using the included bracket, hardwire one end of the included pigtail harness directly into your vehicle. The other end plugs into the brake controller. To transfer the TriFlex to another vehicle or to remove it for storage, just unplug the unit and remove the screws that hold it place in the bracket. Curt offers a spare mounting bracket (C51144 - sold separately) that can be used to affix the TriFlex in your other automobile.

Installation Accessories

For even easier installation, a vehicle-specific wiring adapter (sold separately) is available for most newer trucks and SUVs. One end of the custom adapter plugs into your vehicle, and the other end plugs into the controller - no hardwiring required.

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

See also etrailer.com's exclusive 7- and 4-way brake control installation kit (ETBC7 - sold separately) if you don't already have a 7-way plug at the back of your vehicle.

Surface-Mount Technology

Curt's TriFlex brake controller is built using surface-mount technology (SMT). This method of construction involves soldering electronic components directly to the surface of a printed circuit board. SMT eliminates the need for leads, which are used in older through-hole technology. The result is a circuit board that is smaller yet provides more routing area and that offers superior performance, reliability, and durability.

Curt SMT Circuit Boards

Circuit boards constructed using SMT have been shown to perform better under rough conditions with excessive vibration than those made using the through-hole method. And where would vibration be more likely to occur than in towing applications? SMT circuit boards also produce less heat, leading to increased durability and longer life. In addition, lower levels of resistance ensure better performance, especially for parts that operate at higher frequencies.

Each Curt circuit board is made using high-quality components that are pieced together in the most technologically savvy fashion, leading to greater predictability and reliability in functioning.

51140 Curt Tri-Flex Proportional Trailer Brake Control

Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In
part number: C51436

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.


  • 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 behind 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. For most applications, this harness is located behind the dash.

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.

51436 Curt Quick Plug Brake Control Adaptor Harness

Customer Reviews

Curt TriFlex Trailer Brake Controller - 1 to 4 Axles - Proportional - C51140

Curt Custom Wiring Adapter for Trailer Brake Controllers - Dual Plug In - C51436

Average Customer Rating:  4.8 out of 5 stars   (264 Customer Reviews)

Proportional brake controller automatically levels when mounted within a 90-degree vertical range and a 40-degree horizontal range. Includes digital display, 9 sensitivity settings, reverse-polarity protection, and continuous diagnostics. 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.

- C51140

by: Bill Y.09/28/2015

I installed this unit, hooked up my travel trailer and had it all calibrated and ready to hit the road in less than an hour. Took a 300 mile trip a few days later and the unit was flawless. Forget the old time delayed units, this is the way to go. Also, get the pigtail that is designed for your particular vehicle, it makes installation a snap (plug in to your vehicles available plugin and into the back of this unit) couldn't be simpler. Very satisfied with the unit and with e-trailer.com. Great products, great service. 228079


Still satisfied, works great.

Bill Y - 09/27/2016


- C51436

by: Tommy J.01/31/2014

Adapted Curt brake controller for my 2014 Ford F150 STX without any problems. Just find your Ford brake control connector behind the coin slot on the left side of the dash and plug it in. 115344


After a year of using the Curt brake controller it has been by far the best one of several I have used and installed. i highly recommend the controller.

Tommy J - 01/31/2015


- C51140

by: Tammy H.01/01/2017

I connected the Curt Brake controller into my 2007 Toyota 4runner. It took 5 minutes to hook up using the curt wiring adapter for my vehicle. I pulled a 16' aluminum stock trailer with one horse in it. There were no problems with braking and the braking action was very smooth on the trailer. I also have a weight distribution on the trailer which helps with using the Toyota in an "emergency" tow. The horse had an easy 3 hour tow with smooth braking and no swaying. Thanks etrailer for all the tools that make farm life easier. 329228

- C51140

by: Mike R.09/22/2014

Small size is convenient - easy to mount in a Tacoma. When setting it up for a single-axle 2,200-pound tent trailer with a brand new Dexter axle, I was surprised to find I have to run at the maximum output and sensitivity settings, but it works fine. 152489


Make sure the brakes are properly adjusted. They should be exerting a slight drag on the drum when spinning by hand. If the brakes are not adjusted correctly, you may be exerting more wear on the magnet than is necessary.

-- Patrick B - 09/29/2014


I dont know what changed, but the controller is working as expected now - I am pleased with its performance and convenient size.

Mike R - 09/16/2015


- C51140

by: Alan11/17/2017

2003 Ranger XLT Installation was fun! I tend to ignore instructions especially when those instructions mount the device where my knee is constantly banging into that device. See the photo. Would loved to have a longer extension cable to reach into engine compartment. If you are not mechanically and electrically gifted, have somebody that is do the installation. Had the device not initialize once at the beginning of a trip. After thirty minutes of trouble tracing, decided nothing was wrong, unplugged the cable for a few minutes then reconnected and initialization completed correctly and I had brakes. Now I unplug the device whenever I'm not towing. 452856

- C51140

by: Jeff H.08/01/2013

Items arrived quickly. Hesitant to buy "Drawtite",as I was told 'Made in China". However, it says on label 'Made in USA'! Needed additional spacer for 'middle' bolt.? Fairly easy install. Curt brake controller should be easy as well. All in all, a 'square deal! 92715


Hitch is fine.Curt controller had a malfunction, factory support -superb! Sent a new unit in 2 days!

Jeff H - 01/30/2015


- C51140

by: Lee A07/23/2013

I received my Curt triflex brake control in less than a week from ordering on line. It was so easy to put in and set up. I couldn't believe it. Just plug and play. 91176


It didnt. It would not adequately slow down or stop my 34 fifth wheel. I pulled it out and installed a Prodigy. The Prodigy works just fine.

Lee A - 01/21/2015


- C51140

by: Tom and Anita09/19/2016

Yes I received my order and installed the brake controller. All seems to be fine, although I have yet to tow with it yet. Here are a couple photos of the installation in my 2010 Toyota Tundra. 296409

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by: Kevin L09/12/2013

So far , so good . Install took a whole 5 minutes and the overall size is easily dealt with in my Tacoma . Nice to have the led display - not too bright but easy to read and understand diagnostics and output levels . The compact size is a real bonus and it's controls are easy to understand , no complaints at all . Best is it's bracket system - screw holes to mount to the truck side are outside of the main bracket dimensions which allows a lot easier install - great intuitive design instead of trying to position , remove controller and mark holes . I was able to actually drill right past the controller in-place and install the screws , dead simple . Kudos to Curt for a great design/product . 99562

- C51140

by: Joe R04/24/2014

placed into my 2014 RAM 1500 put it in place only took about a half hour with the right harness. 127226


Just curious, how much weight have you towed with the controller and how well did it perform? What setting did you run?

-- comment by: John P - 09/26/2015


Hi John I have a ram 1500 V6 . My camper is 19 ft about 4300 LBSI have the sensitivity setting at L7 and the thumbwheel set around 20 to 25 .. If every thing reads ok from the codes .the setting are easy to test with a short drive .Adjust your settings to your liking. after setting for awhile like over the winter or pulling out from a seasonal site you may need to run little heaver on the break for a short time . It has plenty of power to stop you with just the trailer brakes .

-- comment by: Joe R - 10/13/2015


- C51140

by: Chris H07/31/2017

I purchased this controller along with the direct fit wiring harness and 7 way trailer harness for my 2000 F250SD. Install was easy. I would highly suggest buying the direct fit harness with this controller (I was replacing a spliced in system that was having intermittent issues). The only trailer I tow with brakes is an 18' landscape/utility trailer that may be loaded with 1000# one week and 7000# the next, so the inertia driven system should make for a much smoother ride. Service was great, really appreciated the follow up email to make sure the product arrived in good order and all my needs had been met. Etrailer will be my first stop for trailer related needs in the future. 412923

- C51140

by: Bryan07/15/2018

This was my first brake controller. Installation took me about 40 minutes. Having the truck prewired means its as simple as plug and play. As soon as I powered it up it worked, and calibration once I was hooked up to a trailer took just a few minutes. So far I'm pleased. I'm still working on the right settings but I would definitely recommend this unit. Also staff at Etrailer were very helpful. The first controller I ordered had the cable out of stock. They emailed me right away and helped me pick one out that was in stock and arrange the two day shipping I needed. This was on a Friday evening, so many places would have waited until Monday to let me know. 541910

- C51140

by: Ryan R04/12/2015

Installation was easy. Product works well. The power and sensitivity adjustments are very useful. 184853


Everything is still working fine.Thanks for Asking

Ryan R - 04/21/2016


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by: Bill B06/09/2014

Good buy, very easy to hook up and worked well. 134871


Im still using the above items and have had no problems with them. Thanks.

Bill B - 06/09/2015


- C51140

by: Howard S.04/06/2017

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%! 363500


Still using the products no problems, everything’s works great.

Howard S - 04/06/2018


- C51140

by: Steven08/29/2018

I wasn't very pleased with this brake controller. It seemed to frequently require resetting, which involved stopping, getting out and unplugging/replugging the brake cable. I was never able to get a good understanding of the controls either - there was a dial for gain and a slider for "aggressiveness" (huh?). Also, after using it for about 10 months, I thought the brakes on my trailer needed replacing - it would brake some, but not much. About that time I bought a new truck with built-in brake controller and the trailer brakes worked great again. Had to be due to the controller... 559619

- C51140

by: Robert07/15/2018

Item is smaller and lighter than expected. Easily mounted using existing dash screw. Pigtail wire kit that was also ordered here made installation a snap. I like the display and the ability to manually apply trailer brakes and increase braking force on the fly. Less than a 5 minutes install. Installed only, haven’t used it yet. Will have to update later. Rig is 2007 Dodge Ram 2500 4X4 CTD. 542058

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by: Lyn J.03/31/2017

One of the best internet companies that I have ordered from and I have ordered a lot over the years. Kim was excellent help with my order. I elected for free ship and my order was packed and shipped out on Sat. And received on Wed. Pricing was about half of what my local trailer retailer ask. Bottom line, order from these people and you will not be disappointed. The Curt controller was very easy to install and adjust and works perfectly. The ball mount is massive, no worries about breaking this monster ! Very pleased with every aspect of this purchase. 362878

- C51140

by: Joe B.11/21/2015

Easy to install and set up. I can't believe the difference between this proportional controller and the simpler time delay type. Between the power output adjustment and the sensitivity adjustment, you can quickly and easily adjust the controller for your trailer. It took me about 5 minutes to dial it in perfectly! No more jerky trailer brakes! Thank you E-Trailer! 232383

- C51140

by: Vincenzo09/05/2018

Wow! All works to perfection ! From the Website wade of specification of what I needed for my set up to fast delivery and plug n play install ! This is my second order from etrailer & will be for all my needs! I installed it to my right knee side , so not to hit it in & out daily, but any place will work - tie up extra wire securely. Safe journey !! 561685

- C51140

by: Jonathan07/26/2018

This is a great product that I have owned for about a year now. Installed on my '17 Ram 3500 DRW that I am using commercially along with a 46 ft. flatbed car hauler trailer. I have reached up to 35,000lbs gross combination weight (power unit and trailer combined). Have not had any issues with this product so far besides the self recalibrating which is normal every once in a while since I use the trailer more than the average RV hauler along with more weight. Would recommend this specific brand and product over and over again. 546281

- C51140

by: William g09/22/2018

Fortunately my F150 had the trailer package so the pigtail plugged right in. Only snag was I had to fabricate a piece to attach to the instrument panel (lower right) to get the correct angle they specify. That took some work. But it all came together nicely. See attached picture. The brake control works great. Good price. 567828

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by: Mainly Dave07/22/2015

Installed and use on a 2014 FJ Cruiser. Need the wiring kit for the FJ. Installation was straight forward and everything needed was included. Took me about 2 hours but no problems. Using the unit is easy to understand. My only concern is that it does not seem to be able to lock up the brakes [even with the manual function.] But this might be due to my brakes being worn and not used recently. Have towed a fairly heavy load once [~3500 lbs,] and I am pleased with the braking function. I recommend the product. 213490

- C51140

by: Mark from Pa10/13/2013

Was very easy to install. Shipped out same day. I'm very particular so install took longer than necessary about 20 minutes. I don't like having extra holes or things mounted crooked on my truck. Used it same day I installed it to haul our livestock trailer. Worked great braking was very smooth. Can't say it is better or worse than any other controller but I am happy with this one. 103662


mark question for you is breaking between having the trailer load with livestock to empty is there lots of adjustment or no problems

-- comment by: mike - 04/10/2015


- C51140

by: OEM09/24/2017

The screws for the bracket did not fit into the plastic bushings in the bracket. I have got hooked this up to a trailer with brakes, yet, but everything else seems to work, including the adapter for my Silvy1500. Note that this review bears no negativity on etrailer, but he manufacturer of the brake controller. Stop letting China manufacture our goods and get better product reviews. I have had good experiences with etrailer.com, they always ship fast and deliver quality installation guides. Kudos to them! 435970

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by: Wayne08/19/2016

Quick and easy to install with the included C51451 wire harness. Start to finish was less than 5 minutes. Setup and adjustment was also quick and painless. What really made the 5 star rating was their lowest price promise. After my purchase I found it for a lower price elsewhere. A quick message to etrailer was all it took, with the details of where I found it and the price, and my card was refunded the difference plus a little more! This was my first purchase from etrailer and it will not be my last. 285587

- C51140

by: Greg C.08/04/2015

After talking at length (at least 15 minutes) to the rep on the phone, I choose the Curt TriFlex controller for my 2015 Silverado. It happens to be the same unit sold on Chevy's website (but cheaper on etrailor). The sales person was awesome! She wanted to be sure I got the right one, not trying to upsell me on something I didn't need. Just as she promised, it plugged right in under the dash and I even used an existing screw to mount the bracket. A 15minute install!!! I will shop here again. 216669

- C51140

by: Robert A.04/21/2017

The unit with the matching installation cable was easy to install once I found the factory installed plug-in port on my 07' Dodge Quad Cab. The videos didn't have my truck model and I had to go to the Curt mfg website to find a picture of the the location of the port. I have not hooked up the truck with the trailer yet to test and adjust the brakes but the controller installation and functionality test was very easy to accomplish and went smoothly with the instructions provided. 370441

- C51436

by: Mark A.11/18/2013

Etrailer provided outstanding information regarding the technical details of the product along with easy to understand installation instructions. The brake controller provided a cost effective solution for my basic requirements. The installation was a "snap", the only time consuming task was determining the optimal location/position install the brake controller. Item was installed in a 2013 Ford F150 and I use it on a dual axle trailer for hauling a compact Kubota tractor. 107754

- C51436

by: 2012 ford F15- trailer brake06/08/2016

Excellent - no hesitation in making that evaluation I bought a brake controller, interface cable for the F150, and the 7 pin plug that goes on the back bumper. All items are great quality. Parts arrived as expected with shipping as paid for. I am installing the equipment, but don't have any issues. There were no installation instructions, however these are available on line line detail. I do not expect any operational probems but am a few days from making that test. 258882

- C51140

by: Jason S07/30/2017

I recently bought a Kurt trailer brake controller with adaptor. I have to say, that it was the easiest thing to hook up. The product was also shipped to my home very fast. I did not think I was going to receive the package until the next week, but it came just in time to use it the following day for my work. i Love ordering products from etrailer, I have only had really great service and good products from them. I will for sure, order from them again. 414526

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by: Jared S.10/12/2017

The trailer brake worked out very well. Installation was a little difficult for someone with no experience, but the videos on etrailer were great. My only issue would be that I only had about a foot of spare cable left at the end of the install, a few more feet would have helped me feel more comfortable. Otherwise, great product and site. Having all the right equipment and videos appropriate for my Jeep were essential. 442038

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by: Rae W03/05/2017

I reviewed the connecting cord thinking I reviewed the whole thing but apparently not. This controller was great right out of the box. A you-tube quick review and installed myself in 1/2 hour. It worked fabulous as used it over the weekend. It seemed to set itself up for the best brake response and it sure worked smoothly. I am towing a 21 ft trailer with dual axles weighing about 45oo lbs and towed by a Buick Enclave 348888


It is a wonderful product. Easy-to-use, easy to install

Rae W - 03/21/2018


- C51140

by: Brian12/12/2017

I installed this item on my 2009 F-150. We will mainly be pulling a 17' Ice Castle toy hauler/camper/fish house. The product shipped in a timely manner, and couldn't have installed easier. For the money, you can't beat etrailer.com. If you take your vehicle to the dealer, expect to pay twice the money. Watch a few videos, read the directions, and you should be good to go. Thank you etrailer for a fine product. 459430

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by: Doug S09/15/2013

To be honest, haven't installed yet. Have to run wiring in 2 trucks as neither has factory wiring. I want mounting to be not noticeable if I sell either vehicle. Based on reviews, and having my hands on it and the printed directions I believe it will fit my greatly fit my needs. I have a one month plus to get one vehicle ready for a road trip. LOL, I like to plan ahead. Will write more when I get working. 99999

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by: Larry H08/23/2017

I haven't used it yet, because I cannot seem to get it wired correctly. It had good reviews and my son purchased this unit for his new truck and trailer about 6 months ago. He personally recommended it for me. But I have yet to see a video by etrailer or anyone else showing exactly where the brake light wire is under the dash for my '95 Suburban. I have paid 2 techs to wire the red wire.....wrong. 424375


Larry, after reviewing your order notes today, I see that your 3rd mechanic was able to find the wire. Some models do have the brake blue and hot lead orange or red wires already ran from under the hood to the end of the drivers side frame rail. However, as you know, these wires are hard to access and additional wire will still be needed. Part # ETBC7
Universal Installation Kit for Trailer Brake Controller - 7-Way RV and 4-Way Flat - 10 Gauge Wires
is still recommended.

-- Laura E - 08/30/2017


- C51140

by: Michael12/07/2017

Product was exactly as described. Was a simple plug and play with the factory Toyota harness under the dash. Once I determined where I wanted my brake controller, simply plug this into the factory harness and the other pigtail into the Curt controller and that was it ! Incredibly fast shipping. (was at my door in a little more than 24 hrs !!!) As always, great experience with etrailer. 457988

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by: Eric J05/25/2017

Customer service was excellent! I needed an order rushed, and they couldn't ship to the PO box I provided. They immediately reached out and got delivery information so that my order could be shipped the same day. Very helpful, and very responsive! All the etrailer installation videos and diagrams they provide make the process even better! Would definitely recommend ordering from them. 384717

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by: frank in florida01/01/2014

Shipping was fast and product was exactly as described. It took longer to pull the factory plug from under the dash in my 2004 f250 than to complete the brake controller connections. My truck came factoy with the 7way plug and wiring installed. Adjustments were a breeze and the controller worked perfectly. 10 minutes or less install. I would recommend this to anyone. 111686

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by: Sharon K06/14/2016

Bought this controller for my husband, received it on a Wednesday my husband installed that night. The very next day we left to go up state camping. Going over the mountains my husband kept saying how impressed he was with the break controller. Easy to install. He installed it in a 2006 Dodge Ram 1500, he pulls a 2016, 32 foot camper. I would recommend this product!!! 261392

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by: Dave10/14/2018

I am very excited to try it, however the quick connect, doesn't seem to fit my 2004 3/4 ton Chevy Express van. Th brake control harness #51451. It's for the Trifles brake controller. If it is the correct harness I cannot find where to plot in . The vehicle end of the harness will not fit available spots on fuse block . Any help would be appreciated. Thanks Dave 574308

- C51140

by: George08/26/2018

This works pretty well for my 10K lb Hudson equipment trailer. I've never used a brake controller before and this was pretty simple to operate. It plugged right in to a wire harness under the dash of my 2003 Ford Expedition. The setup instructions were thorough but sounds a little more complicated than the actual usage is. Overall very easy to use. 558237

- C51436

by: Jim S.01/15/2018

This pigtail that Dan T. with e-trailer help me get order an shipped worked perfectly. It was a custom fit for 2016 F-150 w/ no tow pkg and a Curt 51120 brake controller. This will almost complete my conversion of my truck that had no tow pkg. In the end it will help my daughter tow her Shooting S barrel horse safely to the shows. Thank you Dan T. 467325

- C51140

by: Tim03/22/2018

Easy to install, setup, and calibrate to the different weight travel trailers I towed since I bought it. I keep it in the glove compartment and screw it back up in the same holes I originally made whenever I need it. I probably use it 3-4 times a year. Nice to have the added confidence of trailer braves. etrailers service is second to none 488022

- C51140

by: Zachary03/11/2018

I ordered all the equipment to help my son rewire his enclosed trailer. We got everything as ordered and it all worked out great. I had emailed etrailer multiple times to discuss what exactly I needed. They were great and their help was above and beyond. Any trailer parts, wiring, etc., you need, this is the place to get it! 483503

- C51140

by: Matt B.07/23/2015

Easy install. The product works as advertised. Installed on a 2013 Nissan Armada in order to tow our 27' travel trailer, dual axle; I had to mount the controller in a small slot below the stereo due to the fact that it would have been unsafe to install below the steering wheel. The item was small enough to fit perfectly. 213805

- C51140

by: James02/27/2018

It worked pretty well. I still prefer surge brakes. It fried when I hit a bad bump crossing from Ga. to SC on I-95. The impact cut the brake lines on the trailer and shorted out the controller. It wasn't good, because I didn't know until I was in the mountains trying to slow down...Oh well! Still, it was a good product. 479362

- C51140

by: Tom H03/10/2017

The C51140 controller I purchased for my 2016 Colorado was delivered on time, and was very easy to install. Took about 1/2 hour to install, make the initial set points and dial it in so my 18' RV stops nice and smooth. I couldn't ask for anything easier. I recommend this for anyone looking to buy a brake controller. 350930

- C51140

by: Mick12/08/2017

The order was easy to make by navigating the website. To my amazement it arrived 26 hours after the order was placed. I have used etrailer a few times before and am always pleased with their service. Installation of the brake Co troll was simple and the recommended parts were all that we needed. 458511

- C51140

by: Jim H08/28/2015

Brake installed using the pig tail connector in 10 minutes. Initial test and it works very well. Very fast delivery and customer support was very helpful in picking out the right product for my needs. Also, I watched the video on how to install and it was spot on. Made install very quick and easy. 222302

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Ask the Experts about this Brake Controller
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  • Display Code Meanings for Curt TriFlex Brake Controller
  • The Curt Triflex part # C51140 that you referenced should show a single decimal point when there is not trailer connected and two decimal points when a trailer is connected. I attached a couple pictures that show what the display letters/codes mean on your brake controller. Since none of them are two dash lines feel free to check out the picture I attached and see what it might be, or email me back with a picture of the display so I can show it to Curt if your display is different. Have
    view full answer...

  • Installing a Brake Controller on a 2013 Chrysler Town and Country
  • There will have to bee some cutting and splicing to install a brake controller on your 2013 Chrysler Town and Country. Chrysler did not add a factory brake controller harness to the Town and Country, so the brake controller will need to be hardwired. The good news is that you will likely only have to splice one wire into your vehicle wiring. To install a brake controller like the Curt TriFlex, # C51140, that you referenced, you will want the Curt Universal Brake Controller Wiring Adapter,
    view full answer...

  • Troubleshooting Curt TriFlex Brake Controller Showing Overload Error
  • This The OL error you're seeing means that there is a short somewhere in the brake output circuit, which is the blue wire that exits the rear of the controller. The usual cause of this is a corroded or damaged trailer connector, but because this is a recent installation on an almost new vehicle, that's probably not the case. In the install, you ran the gray two-wire cable from the rear of the vehicle. The white wire in the cable should be connected to the blue wire on the 7-way connector
    view full answer...

  • Trailer Brakes On Camper are Humming
  • What you are hearing is the brake magnet being activated. If this is happening immediately upon plugging in the trailer, while the brakes on the truck are NOT being applied, it would indicate that something is wired incorrectly. Does the truck have a 6-way or 6 pin trailer connector? If so, either the connector on the vehicle or the trailer would need to be rewired. There are two accepted methods of wiring a 6-way connector. One method uses the center pin to carry the brake controller
    view full answer...

  • Troubleshooting Curt TriFlex Trailer Brake Controller With Erratic Digital Displays
  • I called my contact at Curt and they told me you can possibly reset the brake controller by unplugging the 12V power form it and then let it sit for a few minutes. Then turn it back on and that may take care of the issue. Make sure the trailer is not plugged in when you do this. Then I recommend checking the trailer plug with the trailer unhooked to see if there is current when the brake controller is off and then check it again when the controller is on. They said the erratic display
    view full answer...

  • Meaning of Error Code RC with Curt Tri-Flex Trailer Brake Controller C51140
  • I could not find purchase history for a brake controller based on your email address but I do note that you referenced a question regarding the Curt Tri-Flex # C51140. With this brake controller the code RC indicates that the unit needs to be recalibrated. You can accomplish this by unplugging the trailer connector from the tow vehicle, waiting a minute or two and then re-connecting it. I linked the installation instructions and troubleshooting guide for this item for your reference.
    view full answer...

  • Troubleshooting OverLoad Code on Brake Controller With Trailer With New Wiring
  • It sounds like you have bad trailer brake magnets on your trailer. Having a bad magnet can cause the problem you described and based on what you mentioned it would be the most obvious issue. I attached a help article that details how to troubleshoot trailer magnets.
    view full answer...

  • Resetting Curt TriFlex Trailer Brake Controller With Unknown Display
  • I called my contact at Curt about the Curt TriFlex Trailer Brake Controller, part # C51140. They told me that you should disconnect the power to the unit and leave it disconnected for 15 or so seconds and then plug it back it. It should recalibrate itself and work fine after that.
    view full answer...

  • Curt TriFlex Brake Controller C51140 Does Not Show Red Dot on Display After Installation
  • The Curt TriFlex Trailer Brake Controller, part # C51140, and the matching harness for your 2007 Chevrolet Silverado Classic, part # C51352, will work with your vehicle as long as your 7-way connector on your rear bumper is not the type that includes LED test lights. Such 7-way connectors are not compatible with the Curt TriFlex. It is critical that before installing the controller the negative battery terminal be disconnected to avoid potential damage to the unit. Also, the trailer
    view full answer...

  • Does the Curt TriFlex Brake Controller Need to be Disconnected when Backing Up
  • You should not have to disconnect the Curt TriFlex Brake Controller, # C51140, when backing up. Brake controllers are designed to send power to the trailer brakes when you step on the brake pedal. When backing up, you typically step on the brake pedal several times, so many people simply disconnect the trailer connector from the tow vehicle before backing up. The Curt TriFlex brake controller is a proportional brake controller that uses an internal inertia sensor to sense the braking
    view full answer...

  • Constant Voltage on 12V and Brake Controller Output Wire with Curt TriFlex Trailer Brake Controller
  • When testing the wire functions after installing the Curt TriFlex Trailer Brake Controller # C51140 and Wiring Harness # C51515 in your 2014 Toyota Sienna, it is normal for both the 12V and brake lights on a tester like # TR20117 to light up without actually activating the brakes. This is because the brake controller sends out a small trace current to look for a completed circuit. I have attached a demonstration video on a similar 7 Way Trailer Connector Vehicle Tester # TR20117 that shows
    view full answer...

  • LED Display of Curt TriFlex # C51140 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...

  • Curt Brake Controller Flashes Numbers when Braking and Not Towing with a 2011 Ram 1500
  • Curt brake controllers such as # C51140 can be very sensitive and it is not uncommon to get something on the display with no trailer attached. But what I recommend is to make sure the 7-Way connector at the back of the truck is clean and free of corrosion and moisture inside where the wires attach and outside on the pins. Corrosion or moisture can cause a short and cause the brake controller to do strange things.
    view full answer...

  • Troubleshooting Brake Controller That Gets Hot and Trailer Brakes that Lock Up
  • It does sound like there is a short on your trailer. If the brakes locked up and the brake controller unit got very warm it sounds like there is a short on the trailer's 12V power circuit that is causing the electric brakes to lock up. It is possible for different circuits to become bridged together and your 12V power feed might be getting to the brakes. First, check the trailer plug inside and out for signs of corrosion. Even slight greenish or whitish discoloration can indicate corrosion.
    view full answer...

  • Troubleshooting Curt TriFlex Brake Controller Showing Flashing DC And Locking Brakes
  • I reached out to my contact at Curt and the DC flashing on your Curt TriFlex Trailer Brake Controller # C51140 is showing that your trailer is disconnected from the brake controller. This code is telling you that there is an issue between the contoller and your trailer brakes, that there is a short somewhere. This could be corrosion at the connection, a nick in the wire somewhere or a short on the trailer itself. I recommend checking your controller first. Using an incandescent
    view full answer...

  • Parts Needed to Install a Curt and Tekonsha Brake Controller in a 2014 Ram
  • You do NOT have to install the Mopar brake controller in your 2014 Ram 1500, you can use an aftermarket controller like the Curt Triflex Brake Controller part # C51140. All you would need for the installation would be the Curt Custom Wiring Adapter # C51453 that you also referenced. To see how this harness installs in your vehicle check out the installation instructions I attached. If your old controller was a Tekonsha brand the harness you would need instead is the Tekonsha Custom
    view full answer...

  • Brake Controller Recommendation for a 2012 Tiffin Allegro
  • There isn't a plug-in adapter that would allow for a simple installation of a brake controller like the Curt Triflex Brake Controller part # C51140 in your 2012 Tiffin Allegro, but from the research I did there should be a bundle of wires under your dash that a brake controller would install to. For a Tekonsha brake controller the brake controller we recommend the most is the Prodigy P2 Brake Controller part # 90885. This is the best selling controller on the market because of how easy
    view full answer...

  • Curt TriFlex Brake Controller Shows d.C. and Other Error Messages on 2005 Toyota Tundra
  • The first thing you will want to try is to unplug your TriFlex brake controller # C51140 for about 15 seconds or more. Then, before plugging it back in go back through the instructions as if you were installing the controller for the first time. Once all electrical connections are complete and the single decimal point is seen, while parked on a level surface, plug the trailers electrical connector into the tow vehicle’s plug. Making the trailer connection initiates the mounting position
    view full answer...

  • Can Curt TriFlex Trailer Brake Controller # C51140 Be Temporarily Disabled When Backing Up
  • I did some research on this controller for your 2006 Chevrolet Silverado, and there are no features available that will turn the Curt TriFlex Brake Controller, part # C51140 off. The best way to temporarily disable the controller when you intend to back up is to unplug the trailer. If you were to unplug the controller, it would have to be reset when it is plugged back in. I spoke with my contact at Curt and they strongly advised against doing this because if someone failed to reconnect
    view full answer...

  • Hardwiring in a 7-Way Trailer Connector and Brake Controller on a 2018 Ford F-150 w/Factory 4-Way
  • I did some checking and right now, in order to add a 7-Way trailer connector to your 2018 Ford F-150, you will need to use our hardwire kit # ETBC7. The factory brake controller wiring harness might be in place but if it is for sure and if that means you can install the Ford brake controller I cannot answer. I am sure you can though because I know in other Ford F-150s you can. Or you could install an aftermarket brake controller using wiring harness # 22292 and a Tekonsha brake controller.
    view full answer...

  • Which Curt Brake Controller Adapter Fits a 2015 Ford F-150
  • The Curt adapter, part # C51436, fits your 2015 Ford F-150. It plugs into the factory connector under your truck's dash and fits most Curt brake controllers, like the Venturer part # C51110. I've linked a video of a controller being installed into a 2013 F-150 using the # C51436 adapter.
    view full answer...

Info for these parts were:

Test Fit:
Joe V
Edited by:
Leah B
Photos by:
Jackie C
Expert Research:
Michael L
Video by:
Andrew K
Written by:
Lindsey S
Expert Research:
Michael H
Installed by:
Jeff D
Expert Research:
Jameson C
Video Edited:
Joshua S
Test Fit:
Nicholas E
Video Edited:
Jacob T
Test Fit:
Rick A
Expert Research:
John H
Updated by:
Adele M
Video Edited:
Andrew L
Expert Research:
Adam R
Video Edited:
Kathleen M
Test Fit:
Shane T
Expert Research:
Rachael H
Expert Research:
Jeffrey L
Video Edited:
Sue W
Test Fit:
Randy B
Video Edited:
Chris R
Updated by:
Sarah W
Updated by:
Amanda M
Video Edited:
Zach D
Test Fit:
Brent H

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