Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.
Part Numbers: C51120,C51451
Electronic controller activates electric trailer brakes with a preset intensity when you apply the brakes in your vehicle. Power output and braking aggressiveness are easily adjustable. Includes easy-to-read digital display and manual override.
The Discovery applies your trailer's brakes when the brake pedal in your tow vehicle is engaged. Every time you apply the brakes in your vehicle, a signal is sent - via the brake switch - to the Discovery. The controller then sends power out to your trailer brakes to activate them with an intensity set by you, at a rate determined by you. Both the amount of braking power (output) and rate of application (sync) can be adjusted to suit your preference, the road conditions, type of trailer, and size of the load. To determine which levels are best for your application, you must test out your towing setup and choose what feels best.
A time-delay controller is so named because there is a delay between the time that you initially apply the brakes in your tow vehicle and the time that the controller reaches maximum power output. Unlike a proportional brake controller, which activates your trailer's brakes based on the deceleration of your tow vehicle, the Discovery sends power out in the same way, with the same gradual delay, no matter the braking situation. Although this delay always exists, it can be adjusted by changing the sync setting.
The above diagram shows the controls and components of the Curt Discovery trailer brake controller.
During the initial setup process, use the thumbwheel control on top of the Discovery 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. This setting ranges from 0 to 10, with 10 indicating maximum output.
To adjust the aggressiveness of your trailer's braking action, use the slide-bar control on the side of the Discovery to change the sync setting. If you want to reach maximum power output faster, move the switch forward. To get smoother braking action, slide the switch backward, thus supplying power to the trailer brakes more gradually. You can alter the sync setting to suit your driving preferences or to improve handling based on changing road conditions or varied trailer loads. The digital display will only show the sync setting as you adjust it.
Quick, Simple Installation
Because inertia plays no role in the functioning of this controller, you do not have to mount the unit at any particular angle. As a result, mounting options are limitless, so long as you can still easily access the controller.
Installation of the Discovery requires that you either purchase a custom wiring adapter designed to plug into the controller or that you hardwire the controller directly into your vehicle. To hardwire the Discovery, you must remove the plug at the end of the integrated wiring harness.
For 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.
Install your Curt electric trailer brake controller quickly and easily with this custom wiring adapter. Simply plug one end of the adapter into your controller and then plug the other end into the built-in port beneath your vehicle's dash.
To install your Curt electric brake controller, you need to connect the wiring of the controller to your vehicle. Certain auto manufacturers offer pre-wired options, typically known as tow packages, wherein wiring is run for you from the dash to the trailer connector on the back of your vehicle. When this is done, a port is installed at your dash so that you can easily plug in a brake controller.
This adapter plugs into the port on your vehicle's built-in brake control wiring harness. The port is located in the wiring panel underneath the dash, to the left of the steering column, near the emergency brake pedal.
No hardwiring is required to install this adapter. After you plug it into the factory port, you simply plug the other end of the adapter directly into your electric trailer brake controller. Because there are no wires to connect, installation is not permanent. You can unplug and remove your brake controller at any time to transfer it to another vehicle or securely stow it away.
Video of Demo-Curt-Brake-Controller-C51120
Videos are provided as a guide only. Refer to manufacturer
installation instructions and specs for complete information.
Today we're going to take a look at the Curt Discovery Trailer Brake Controller number C51120. This time delayed brake controller activates trailer brakes with a preset intensity. The signal is sent to the trailer brakes when the tow vehicle's brakes are activated.It has an adjustable thumb wheel power output that allows you to determine the amount of breaking force you would set to the maximum when you travel through a more hilly terrain with a fully loaded trailer and you would back off the power output when you're towing a smaller more lightweight trailer.It also features a sink switch here on the side. It allows you to adjust the aggressiveness of the brakes. If you want it full power in this position right here. It will increase the activation speed of the brakes and you would move it back in the opposite direction to achieve a smoother braking by supplying the power more gradually.
It has an easy to read digital display that communicates brake force output, sink setting and air codes and we'll attach this to a power supply in just a moment so you can see that a little better. Self-diagnostics function monitors the trailer connection and checks for shorts. It has a built in slide bar emergency manual override and again we'll discuss that more in just a moment. It has also has a quick and easy installation. It comes with the mounting bracket right here.
The screws to attach the bracket to the controller as well as a quick reference card if you have any questions. One of the differences between the time delay brake controller and a proportional brake controller is there's no need to mount this one level the way you would a proportional controller.You can mount it up, down, side to side, as long as you can see the digital display you're good to go. This application is for trailers up to four axles or eight brake assemblies. It's designed for use with electric brakes only and it does have a limited lifetime warranty. Now we're going to attach it to our power supply and the wiring harness that we're using here is the Curt Universal Wiring Adapter for Curt Trailer Brake Controllers, number C51515.
This particular harness ends in a pigtail and it is intended for vehicles who do not come with a factory installed brake controller port. Now when you hit the brake you will be able to see the digital display and say right here we'll use our output knob here. You can go from zero to ten and we'll set that at five for right now and over here our sink all the way to nine and then slide it back to zero. We will put that at five as well. When we talk about our emergency manual override say youre in traffic and somebody cuts you off and you have to hit the brakes really quick what you would do is hitch your emergency manual override and instead of the normal amount of time it would take for the trailer brakes to brake this removes the time delay function and the maximum output that you had preset it goes to the brakes immediately to help slow you down to prevent any accidents.
That should just about do it for our Curt Discovery Trailer Brake Controller number C51120.
Ask the Experts about this Brake Controller
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Average Customer Rating: 4.8 out of 5 stars (63 Customer Reviews)Electronic controller activates electric trailer brakes with a preset intensity when you apply the brakes in your vehicle. Power output and braking aggressiveness are easily adjustable. Includes easy-to-read digital display and manual override.
by: Randy G01/04/2014
This is an outstanding product - exactly as described. I installed it into my 2005 Ford F150 XLT Extended Cab. Took longer for me to decide where to put it than the actual installation, which took about 3 minutes. My truck had the tow package so the harness - which was included - was an exact match to my truck's harness plug on the right side of the dash in the driver's area. Extremely satisfied. 111895
by: Mark Mason03/19/2014
I always get excellent products and advice from Etrailer will keep comming back 121339
by: J.C. from Bay City02/24/2014
Ordered a brake control and an inline circuit breaker on Feb 11th and shipped the same day. I chose the least expensive shipping option (my bad). A combination of UPS/US Post Office, or so I was told after calling to find out where my shipment was. Tracking info said delivery by the 15th. When it didn't show I called etrailer and was told the post office had it and it was out for delivery...2 days later I finally received it (Feb 20th). I ordered a hitch a couple of weeks prior and received it in 2 days. A 49lb hitch vs a 1lb (maybe) package. Not etrailers fault but I can see why the post office is going broke with service like that! 117375
by: Patrick T.01/23/2014
This controller work great in my 2008 Tundra, and is very easy to set up and adjust. 114575
This is a very small brake controller unit. I had to find the right spot to mount so my knees didn't bump it when I got in and out of the truck. Once the perfect spot was found, the installation was a snap. I used the correct wiring harness to make installation easy. Just snap into back of controller and then into the truck's brake controller wiring harness in the back of dash. It was the simplest install I have ever used. Thanks!!!! 111474
I purchased this item with the premade connection wire for my 2010 Dodge Ram with 7 way trailer wiring adapter. I had this installed in less than 12 minutes! Plug the harness in and mount it you are done! Shipping was super fast had my item in 3 days. The best part is I can remove this when I am not towing my RV so that I keep the stock appearance of my truck. Best online buying experience ever! 100495
by: Rock W.07/29/2013
I chose this brake controller because it was like one I had before so no learning curve needed. Plus I didn't want to mess with extra install concerns of the proportional type controllers. With the video install tips the shade tree mechanic is back in action. With the yr/make/model suggested cable, hook up was a breeze. Ready to do some camping. Thanks etrailer 92116
by: e whitestone12/03/2013
Much, Much better than the proportional type I had before. The proportional types have to be mounted level. This Curt solid-state digital never needs to be level, in fact it could be mounted upside down and still work. No problem finding a place to mount, since it doesn't have to be level. A great price at etrailer makes it that much better. 109008
by: David C.05/17/2014
I purchased this controller for a 2006 4 horse stock trailer & a 2006 Dodge Ram 2500 pick-up truck. The installation video from etrailer was very informative & the instruction from the product was very through. I was able to attached the controller & tested it within one hour. I've towed with the trailer since then & it's working great. 131087
Good quality brake controller for my needs and although I had some issues installing it, etrailer was right there, they helped me troubleshoot my problem and it ended up being a fuse that was not installed apparently by Honda for the ebrake. I popped the fuse in and walah the controller worked perfectly. Thanks Etrailer!! 159127
Product came on time and connector was correct for my vehicle. Controller is small and blends in with vehicle interior. I like the digital readout but the adjustment range is a bit difficult to get right, hopefully I will find the sweet spot between the power and the sync. For the price I like it. 176409
by: Dave C04/09/2014
With the factory adapter the total installation took 5 minutes including a fight with a tangled extension cord. Worked awesome. Towed a 8500lb load up and down the Appalachian range without any worries. Thanks again for the fast shipping, awesome product and great customer service. 124394
I just received my Curt new brake controller and Etrailer truck brake harness. The package arrived promptly - earlier than expected. The harness kit has everything I need and looks like it is well made. Can't wait to get it all installed and try it out. 111247
by: Erik O.08/05/2013
So far so good. Product seems well made. Installation was a breeze. 5-10 mins. Ordering was simple. My Order was upgraded to faster shipping at no additional charge! Fantastic company! Will be ordering from etrailer.com in the future! 93288
by: Jared H.06/25/2013
Great product for the price. This was my first brake controller and it was very easy to setup and mount. I bought the adapter cable for my truck as well and it made it even easier. For the price you cannot go wrong with this. 86013
by: Mike N.05/18/2015
Installed and worked as advertised. I would have given it an excellent rating but I think the braking adjustment wheel is a bit finicky, it takes a little finesse sometimes to get it set exactly how you want. 194052
by: David Williams02/05/2014
I was able to install the brake control in about 15 minutes using the wiring adapter that matched my truck. Have not had a chance as of yet to try out the controller pulling my trailer. 115860
by: Ed D.08/05/2014
Installed controller and connected trailer. Paired with the mating factory connector cable, everything was installed and working in 20 minutes. Controller operates as expected. 144475
by: Fabio W08/07/2013
Order it on Friday got it on Wednesday ! Fast service. Installed it in 5 minutes while cooking on the grill. Works very good for price! Will buy again when I get a new truck 93826
by: Bill C04/10/2014
Everything was easy to install thanks to the Etrailer video on Youtube. I got it all done in about 20 minutes and it all works great. I highly recommend this company. 124478
by: Gary W.12/16/2014
Controller works great. Also, good support from e-trailer. I emailed in on a question about wire size and got a fast answer. Product and e-trailer ROCKS for me !! 165648
by: Sean K11/11/2014
Hardest part was screwing it in took 5 min to complete shipped in two days when it was estimated to take 5 with the ground shipping will use these guys again 160484
online instructions for finding factory plug location was excellent, Easy and quick installation and the included manual and card allowed a quick set up. 120166
by: Ronne - Texas09/09/2013
Very quick shipping. Everything I needed to complete the job. Installed and everything worked the first time. Great product and service. 99044
by: Todd B.04/23/2014
Great brake controller and simple to install in a 2012 Tacoma using C51362 adapter. No splicing needed and took less than 30 min total. 126986
by: scott r08/25/2014
finally found time to install brake box and trailer brake backing plate , both work great ! thanks for great price and fast shipping 148260
by: Larry C08/02/2013
fair price,fast shipping,great product,easy to follow instructions,mounted easily and works great.thanks for the free how to videos. 92919
Bought this with the adapter and it works great. Didn't have to cut any wires - easy adjusting levels and bright digital display. 138479
by: Kevin D.06/06/2013
Simple, fast, Perfect deal. Easy install, my 9 year old could have done it. Very fast shipping, HIGHLY satisfied. Thanks!! 83549
by: Steve F.05/15/2014
Great product, service and fast delivery! Very easy hook up (one plug) and easy to read/understand directions included. 130858
Great product for a fraction of the cost of other name brands! I would not hesitate to purchase this product again. 106186
by: Cliff W.10/16/2014
Great product for the price. Very easy to install and easy reference card makes getting it up to speed very easy. 156246
by: cliff j01/15/2015
Easy hook up. The only thing I don't like is the Manuel assist button feels cheap but other than that it's good. 169036
by: David M.09/08/2013
Very happy with brake controller. Took 5 minutes to install in my Frontier truck. Very easy. Thanks 98869
installed easily, instructions to adjust settings very easy to understand worked great. 111420
by: Dani T.10/21/2014
Great product and really great customer service! I highly recommend this company. 157028
by: DIETER S.07/14/2014
Just what the doctor ordered, easy installation, and works the way I had hoped. 141158
Excellent product, fast delivery,great instructions. Perfect service. 162059
by: tom s07/08/2014
have not installed looking to do in a week or so. should not be 2 bad 140044
by: Pete R.05/22/2014
Easy to install. works great! wallet instruction card is great idea. 131966
by: Jeff H.06/16/2014
Great product....easy to install.....great service and follow up. 135764
by: Jimmy C02/17/2014
Quick delivery and great product that was easy to mount. 116700
by: Keagan P.07/26/2013
Excellent brake controller. Works perfe ctly. 91756
Installed in 2 seconds. works like a c harm 132543
by: Ben S.09/13/2014
Works very well. Easy to install and us e. 150930
by: Ron H04/23/2014
Great product and price. fast shipping. 126755
by: Chris L.09/19/2013
Easy install. Works just like it should. 100557
by: Ken H.08/26/2014
works well, easy install and adjustment 148795
by: Gerry G.06/09/2013
Excellent product. Very user friendly. 83872
Worked just as advertised! Very easy! 104414