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  1. Trailer Brake Controller
  2. CURT
  3. Electric
  4. Electric over Hydraulic
  5. Proportional Controller
  6. Under-Dash Box
Curt TriFlex Trailer Brake Controller - 1 to 4 Axles - Proportional

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

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Our Price: $111.95
Trailer Brake Controller
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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. Lowest Prices for the best trailer brake controller from CURT. Curt TriFlex Trailer Brake Controller - 1 to 4 Axles - Proportional part number C51140 can be ordered online at or call 1-800-940-8924 for expert service.
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CURT Trailer Brake Controller

  • Electric
  • Electric over Hydraulic
  • Proportional Controller
  • CURT
  • Under-Dash Box
  • Up to 4 Axles
  • Automatic Leveling
  • Dash Mount
  • Digital Display
  • 90 Degrees

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'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

Item # C51140

Installation Details C51140 Installation instructions

California residents: click here

Customer Reviews

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

Average Customer Rating:  4.7 out of 5 stars   (479 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.


Wonderful product and product support, I bought a second for my newest truck a 2014 Chevy Silverado LT and the installation was very easy thanks to the videos. I put it where the ash tray would go if they still had them and when closed you cannot see it.


Works well and not a bad install with the etrailer videos, my 97 Dodge Ram Sport 1500 5.2 is a””Wood” truck so I installed the truck flex where the ashtray was, works well


Fairly easy to install and set up. I set it up in a 2013 DODGE Durango and pull a 5200# camper with electric brakes. Stopping is very smooth and controlled.

Still like it
Bill A - 04/07/2021


Great controller! Easy to adjust even on the fly. I had the controller adjusted a little aggressive and as I was trying to get out of Buffalo to go south for the winter we ran into some snow accumulation and was able to quickly dial back the controller to avoid locking up on thick snow covered roads. Literally a potential disaster! Very happy with the controller


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

Still using the products no problems, everything’s works great.
Howard S - 04/06/2018


Easy to set up and operate. The controls are less than intuitive. There’s a sensitivity dial and a force level slider that seem to affect the application of the brakes. It’s not exactly clear which one is more important or has the most impact. The unit works well at highway speed but at low speed operations seems to apply the brakes aggressively to the trailer. This is my first experience with a brake controller so can’t compare with other units. It does make parking lot operations somewhat clumsy. It definitely gets the job done though.

Poorly. The tekonsha prodigy is so much better than this unit.
Jason J - 06/25/2020


this product nearly killed me. in February of 2020 I was towing from Philadelphia area to Miami. Getting off the ramp of 95 at S.O.B. I depressed the slidding button for added braking and I heard a tiny snap and the button stuck in. we skidded to a stop and put flat spots on out tires. turns out the return spring inside snapped off its tiny plastic tab and the brakes locked on. cheap [foreign] crap strikes again. when will we pleas make this stuff in amarica again ??

Andrew S - 10/01/2021


Worked as desribed,I had no problem installing after watching video.After taking fuse box cover off my wires were hooked up already,no work to do there.For me a straight up easy install that seems to work great.Drove 130 miles after install ,no issues.


I haven't been able to use this yet on a trailer with brakes, but seems to work as described so far. Install was initially a little concerning as the unit's measure input resistance was 1.9 ohms, while OFF). However, once actually connected, and not doing anything, it draws only 22 mA (indicating about 550 ohms, when connected to 12V). This should allow about 2 months of standby on a healthy battery before problems starting might develop. I think it will work out fine. I liked the more intuitive controls on this unit than many of the other brake controllers. Time will tell.....


Watched one of your installation videos. With the factory wiring harness adapter, that came with the Curt Tri Flex controller, installation was a breeze. It took longer to decide where to mount the controller, than it did to make the electrical connections. Used it with my tent trailer on a 2 day trip, worked perfectly. Very pleased with performance and price. See attached photo of finished installation.


Great product.Works as described. The instructions were well written and video was helpful as well.Would recommend to anyone looking for a good break controller.

Works great.No issues so far other than the little light that lets you know its on.Wish I could shut it off.My truck sets a long time between starts so it probably helps drain the battery a little.Great product and instructionsvideo,easy to install.I would by it again if I ever need one.
Monty - 09/17/2021

The Curt Triflex does have an indicator light that will stay on for several minutes after the vehicle has stopped running. It eventually will go into sleep mode after a period of time. The light pulls such little power that will not drain the battery so you don't have to worry about that.

-- Etrailer Expert Heather A - 9/29/2021


Installation was easy with Adapter cable and Controller which I installed on top of dash board cover and required only one hole to be drilled. Installation location allows for easy access to adjust settings, apply the trailer brakes alone and see the display.
Tough part was locating the 2010 Ford F53, Wennibago, Vista, OEM connector which was out of sight. Remove the dash board cover, which was easy, then look for the big harness (see pictures) and the smaller cable which splits away from it. None of the literature explained that the connector is gray for six pins although only for pins are in the connector. Once found, just plug things together and it all works.


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.


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.


I used one of these controllers for about 7 years before it died...this new one didn't make it to the first trip! This controller died on testing right after installation, initially indicating an overload on the trailer the first time I activated it. After this first message, it constantly indicated that it was hooked to a trailer or that there was an overload condition, even when not hitched up! I could not get it to reset, even after being disconnected for days. I checked my trailer and everything is fine...I spent a lot of time looking for a problem that didn't exist. The new Tekonsha is working fine, so I guess the Curt was a bum controller from the factory. This isn't etrailer's fault at all; I have nothing but things to say about them!


I had to install this and the complete wiring on my 2010 tacoma, it went in in about 2 1/4 hours. clear instructions. Once the controller was hooked up and the trailer on the hitch you didn't even know the trailer was there traveling down the road.


Had same brand unit prior to this one on an earlier truck. Different trucks and trailers. Both hooked right up to truck wiring and adjusted perfectly to get the trailer stopped without drama. Easy to get the trim just right,good confidence builder.


The TriFlex Trailer Brake Controller is just what I needed, it is small, easy to install, simple to operate and gets the job done. If you are looking for a brake controller with fancy displays and flashing lights the TriFlex may not be right for you. The TriFlex is all business and will provide excellent proportional braking. I installed my controller on my F150; I use the truck to tow a 26 foot, 3,500 travel trailer. The truck and trailer both work together with the controller to deliver a superior braking experience.


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.


I got home early today from work and found my brake controller waiting for me.(The one thing I did not like seeing was that, although I have a drop box for all parcels next to the fence, it was placed on top of the box. LAZY DELIVERY PERSON! ) Anyway, I took it in and looked it over and decide to do the install. It took longer for me to get the cover off the box where the plug goes,then to do the entire install. Since I didn't want to drill any holes(yet) I used an existing screw down low. Now, I'm just waiting for my son to bring his dump trailer over,which he will leave with me for a few months. Stay tuned,more pictures and review still to come.


So I installed the brake controller but my trailer is in the repair shop for a lengthy stay and I have not been able to actually use it. I would mention though that the digital readout is not has sharp and clear as portrayed in pictures. That is my biggest disappointment at this time.


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!


This is the second product I have bought here - this unit goes in as described and follow examples on the site you’ll not have an issue. Provided that your vehicle wiring is correct and without faults - expect it to work straight away. Mounting the bracket simple and the wires tuck under the carriage. 5 min install. Now there’s a little learning curve to adjust dependent on the trailer. Thanks e-trailer again for the right stuff! (2002 GMC truck)


Did the job. No complaints. Everything in order and all necessary cable ties etc. I was connecting to a 7 point connector and therefore fed it through the body (already a hole for cables that can be used) under the vehicle as opposed to only hanging through the closed back hatch per one of the videos.

Still ok, but would be nice to have a little more adjustment in the unit to tilt up or down or to unplug easily when not in use and want out of the way. But not a deal breaker.
Evan - 06/14/2021


Install was straightforward and it works great.

Show More Reviews

Ask the Experts about this CURT Trailer Brake Controller

  • How Can Curt Triflex Install in 2015 Volkswagen Touareg
    Installing the Curt Triflex # C51140 is possible in your 2015 Volkswagen Touareg but there are some extra steps for your vehicle and parts you need that you can only get from Volkswagen. If you check out the attached link you can see the overall steps and parts needed.
    view full answer...
  • Curt Triflex Brake Controller Displays 05 and Trailer Brakes Not Working with Brake Pedal
    On Curt brake controller # C51140 there is a 20 display so if the display is upside down is would look like 02 or 05. That message either indicates that a trailer is connected and the brakes are activated or, if it is flashing, that means it is in output adjustment mode waiting for the power output to be adjusted. Try adjusting the power to 2.1 to see if it displays 1.2 or 1.5 and if so then the display is showing upside down. I also recommend cleaning the vehicle and trailer side connectors...
    view full answer...
  • Curt TriFlex Brake Controller Installed on 2000 Jeep Cherokee Shows Only L. and Will Not Change
    The L. display should show up on the Curt TriFlex brake controller, # C51140, when it is plugged in. When you are installing the controller, the trailer should not be connected. The lever or button on the left side of the controller is the sensitivity adjustment. The L. should change when that lever is moved. If it does not then there is likely a problem inside the controller and it will need to be replaced.
    view full answer...
  • Troubleshooting Curt Tri Flex Brake Controller that Locks up Trailer Brakes
    L.1 is the lowest sensitivity that the Curt Tri-Flex part # C51140 can be adjusted down to. However, you can also adjust the overall brake output power with the output control. The output control thumbwheel can be adjusted from the lowest setting all the way up to the highest of 9.9. If you have the controller adjusted all the way down on both of the mentioned settings and it is still locking up then I would assume you have the brake light circuit shorting out to the brake output circuit...
    view full answer...
  • Curt TriFlex Brake Controller Output Numbers Jump when Going Over Bumpy Roads
    The Curt Triflex # C51140 does not have a pendulum. That is an older technology that is not used that much any more. But it still could have been caused by the truck bouncing on the road if it was severe enough. It could also have been an electrical anomaly caused by flex between the truck and trailer connectors or the wiring on the brake magnets moving more than normal from the bouncy road conditions. Make sure the truck and trailer side connectors are clean and free of corrosion inside...
    view full answer...
  • Curt TriFlex Brake Control Shows Settings When Not Connected to Trailer or Locks Up Trailer Brakes
    It sounds like the sensitivity is set high. The closer the sensitivity lever is to the driver, the more aggressive the brakes will be. There could also be a short in your vehicle side trailer connector. Check the vehicle and trailer side connectors for any dirt or corrosion inside and out. A short could cause some of these problems and others. Another possible problem is how the controller is mounted. The controller can only be mounted 70 degrees nose up or 20 degrees nose down. The...
    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...
  • What Problems Does the Curt Triflex Brake Controller Have with 7-Ways With LED Test Lights
    What happens is that the load that LED puts on the brake output circuit tricks the brake controller into thinking that there is a trailer connected and the brake controller will start activating regardless if there is a trailer connected or not. Technically it would work just fine with a trailer, its just that it will always activate regardless if there is a trailer back there or not. I attached installation instructions and an install video for you to check out also.
    view full answer...
  • 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...
  • Brake Controller Recommendation for a 2012 Tiffin Allegro QFA34 towing a Master Tow Dolly
    The Curt Triflex part # C51140 that you referenced would do an excellent job as a brake controller in your 2012 Tiffin Allegro QFA34 towing a Master Tow Dolly part # 80THDEB. You'll have to hardwire the brake controller in, which isn't hard. Check out the FAQ article I attached on installing a brake controller from scratch that will detail the installation.
    view full answer...
  • Curt Trailer Brake Controller Displays Gibberish when Brake Pedal is Pressed
    The brake controller may be trying to tell you something. Take a look at the picture I have included and if what it is displaying is any of these then it is trying to indicate there is a problem. It also could be variable voltage on the input (red) wire or the sensors inside are unsure just how much braking is needed. Make sure the controller is not tilted or turned to one side. You also may need to adjust the sensitivity some (see instructions link). You will also want to make sure...
    view full answer...
    Image 1 for
  • Curt TriFlex Trailer Brake Controller # C51140 Installation in a 2012 Volkswagen Toureg
    To install the Curt TriFlex Trailer Brake Controller # C51140 in your 2012 Volkswagen Toureg with a factory 7-way you will just need to connect the four wires from the controller to the wires under the dash of your vehicle. For more information on this check out the FAQ article I attached to the right. Since you aren't installing a Prodigy brake controller you should not have to use a relay or add an additional fuse. If you experience an erratic display with the controller you will need...
    view full answer...
  • Does Curt TriFlex Brake Controller Have to be Reset and Calibrated Every Time Vehicle Is Turned Off
    No, modern brake controllers such as the Curt TriFlex # C51140 will not have to set up and recalibrated every time the vehicle is turned off. It will keep the settings you use. The connection to the battery is not shut off when the motor is turned off. The controller will still draw power but very, very little so as not to run down the battery.
    view full answer...
  • Troubleshooting Brake Controller that Activates Intermittently When Blinkers are Applied
    Sounds like you are using the left turn/stop circuit from your 7-way for the brake switch wire when you installed the Curt Triflex Brake Controller part # C51140. You would want to go back and find the circuit from the brake pedal switch that only see voltage when the brakes are applied and use it and the problem will go away. Since you used the left/turn circuit of your 7-way any time your blinker is used your controller thinks the brakes are being applied for a second and it activates...
    view full answer...
    Image 1 for
  • Can the Top of the Fuse Box/Power Distribution Box Be Opened Safely on a 2014 GMC Yukon
    You have to be careful with the fuse box or power distribution box on your 2014 GMC Yukon because if you lift that handle (or the whole box) more than 3/8 of an inch it will become disconnected from the vehicle and you will have to have it towed to a GMC dealer to get the vehicle working again! You can take the top cover off though to access the fuses and relays without any issue. You just want to avoid pulling the whole box up. I have included a link to our help article on installing...
    view full answer...
  • Curt TriFlex Brake Controller Turns On with Brake Pedal Even If 2013 Kia Sorento is Turned Off
    Yes. Brake controllers such as # C51140 are connected, in part, to the brake switch on the vehicle. When you step on the brake pedal it sends power along the red wire which is input to the controller telling it you are stepping on the brakes. On some vehicles, like yours, the brake lights will light up even if the vehicle is turned off. So it does sound like everything is working properly.
    view full answer...
  • Should there be a Small Amount of Voltage on Curt Brake Controller Red Wire on 2013 Kia Sorento
    Yes that is normal. The power you are seeing is dead voltage, no amperage draw, and is normal for Curt brake controllers like the TriFlex, # C51140, on your 2013 Kia Sorento.
    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...
  • Digital Display on Curt TriFlex Brake Controller Just Shows an L
    The L. display should show up on the Curt TriFlex brake controller, # C51140, when it is plugged in. When you are installing the controller, the trailer should not be connected. The lever or button on the left side of the controller is the sensitivity adjustment. The L. should change when that lever is moved. You can also try resetting the controller by unplugging it for a few minutes and then plugging it back in (without the trailer connected). If these things do not fix the issue then...
    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...
  • Does Having Curt Triflex Brake Controller On all The Time Affect Lifespan of Controller
    Brake controllers are designed to be on all the time and leaving yours on would not be an issue at all. The reason you don't want to cut power to the controller is that you'd lose all your settings if you did so.
    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...
  • Should Curt TriFlex Brake Controller Cause Shaking During Stopping
    A brake controller should have no affect on the way the truck brakes when a trailer isn't connected. I'd recommend disconnecting it though right now to see if somehow the wiring is causing an issue. If it is the wiring it'll be the red wire of the controller being connected to the wrong circuit. It needs to be on a circuit that only sees voltage when the brakes are applied. It almost sounds like you have warped brake rotors though as that's typically what causes a vehicle to shake or wobble...
    view full answer...

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