Videos are provided As a guide only. Refer To manufacturer
installation instructions And specs For complete information.
Item # C51120
To see if this custom-fit item will work for you please tell us what vehicle you'll use it with.
Orders above $99 qualify for free shipping
Shipping Weight: 0.6 lbs
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.
Video of Curt Discovery Trailer Brake Controller - 1 to 4 Axles - Time Delayed
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.
Average Customer Rating: 4.9 out of 5 stars (121 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: Bob R02/05/2016
I bought a new car dolly with electric brakes to pull with our motorhome ( Fleetwood FlAIR 2001 ) as all states require brakes on trailers at all different weight levels. I called E trailer and spoke with Danna and after talking with her about different models I choose the C51120 time delay control, as it can be adjusted to work well with the tow vehicle . I received the control with in 3 days of the order and went to put it in and found under the dash wire a harness by Fleetwood which told where each wire on the controller went on the harness. I was able to hook it up sitting in the drivers seat. Completed the hook up and started to test the operation, to find I was not getting the proper readings. I talked with Tom and he said he would bench test a like control and report back to me, at 6 pm he left a message on our phone that he believed the problem was along the blue wire to the trailer on the tow vehicle . I started at the back of the, motorhome and moved forward testing for a brake signal, I found that the butt connector had pulled apart and was not getting current to the plug in at rear of coach. Hooked it back together and re taped the wires and it works like a charm. I want to thank all off you for the prompt and knowledgeable service, I would recommend E trailer to anyone who wants to deal with a great staff and company Thank you 237064
by: George D10/17/2015
the brake controller with all the wiring plus the 7 pin plug was better than i thought . it even has great instructions and easy to read. the price was good . the 7 pin plug even has the 4 pin connector mounted in with it very glad that i bought it is everything that you need to make it work . everything about it is excellent very glad that i found it here at a good price . even fast shipping . again thanks for good product 230172
Easy to install and Thanks for the help. 247727
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: Raymond L.05/30/2015
Awesome product. Easy to install and adjust to your liking. Use in combination with the custom wiring adapter for your vehicle and you have a product that can't go wrong! 198827
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: Adam S.06/17/2016
Trailer Brake Assist works as advertised. Installation was challenging but the how-to video and instructions helped. Hardest part was routing the wires without our 2006 Honda Pilot on a lift. Once it was installed I hooked up our trailer and took it to a large parking lot close by to test and adjust the module. I put my brakes on when we first got there and the trailer screeched to a halt, letting me know it was working well! I adjusted it to the recommended setting and it's worked great since. Makes it especially comforting coming down out of the Sierras. I highly recommend trailer.com for all your towing needs. 262275
by: Patrick T.01/23/2014
This controller work great in my 2008 Tundra, and is very easy to set up and adjust. 114575
After reading the reviews of this product I decided to give it a try myself, with a great price. When I received it within a week along with the plug and play 7 prong trailer hitch adapter, I realized I was missing something. The plug and play adapter for this product. It showed me it when I was buying and for what ever reason I didn't have the option to add it as well. It was very easy to install, like I said plug and play. The problem is it does not work. followed all the directions, double checked everything I just don't have a signal to the trailer from the break controller. Good luck 278660
I haven't thought about those products since the day I installed them. That's because I haven't had a reason to think about them again. They have worked perfectly since I bought them. Not only that but, your price, if I remember correctly, was as good as or better than anyone else's. Your website made my purchase easy and I can't imagine that I would buy anything that you sell from anyone else. Great product (I know your company didn't build it but,....) no hassle, quick delivery, and great service. All around good experience. Thank you for checking (great customer service). 355662
by: Edward D07/20/2016
Bought brake controller and custom wiring harness for my 09 Dodge Ram. I've had several Curt brake controllers in other trucks with good results. For the price they are good quality controllers. I've had both delayed time and proportional controllers, both do the job. I prefer delayed time on 1/2 ton trucks since you can set the controller to have trailer brakes apply harder. Installation is very simple, decide there's you want the controller, have 2 screws to hold bracket and 2 screws to secure controller. Took about 5 minutes to install. 274320
by: Drew V.10/10/2016
Installed the Curt Discovery Trailer Brake Controller - 1 to 4 Axles - Time Delayed - C51120 in our 1982 GMC 1-ton dually to activate the brakes on our Forest River Sandpiper Sport SP34T 34' triple axle toyhauler travel trailer... The Curt Discovery Trailer Brake Controller installed easily, adjustment was fairly painless and it performed flawlessly on a recent 600 mile trip. We would definitely recommend this product and etrailer.com! 305035
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: Tacoma Stan09/11/2016
Fit nicely under the dash on the left side. Also installed a 7/4 pin connector in the bumper, replacing the blank plug from the factory(etrailer p/n HM40975-11998) 293471
by: Loren C.06/06/2016
Super fast delivery. Product was just like advertised plugged it in and mounted it and pulled my camper that weekend and it worked perfectly. The item description was very thorough and eliminated buyer mistakes. Order process simple and secure. Definitely would use E trailer again in the future and would highly recommend them to anyone. Thanks. 258339
by: Les F02/20/2017
Dealing with etrailer was a good experience. Shipping was great and everything I ordered was in the package. Having just received the package, I haven't installed it yet but I am sure it will be just what I need. I will certainly deal with etrailer again when the need arises. Thanks etrailer for making my shopping experience hassle free. 343758
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
by: paul t.09/29/2016
great price and great brake controller this is the 5th or 6th time we have ordered from etrailer and we will be ordering from them again as we have had great prices and fast shipping from there products and them. thank you etrailer for keeping the prices reasonable. from --savannah`s secret gardens 301430
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: bill mussell11/22/2016
Brake controller arrived in good time and well packaged. I highly recommend this seller. I won't be installing this for a few months but ever thing looks great. I will be using this on my 2006 ford pick up and towing my 27 ft. travel trailer.BM. 318990
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: Kyle c.04/09/2016
I love this brake controller. It has worked flawlessly since the day I installed it I would definitely buy this unit again. The staff was great and help me troubleshoot. I love that you can adjust it on the Fly depending on the load 243551
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: Greg M.06/21/2016
Installed on my Dodge Ram 1500'l after work today, with the adapter it was easy as pie. This unit was out of stock when I ordered, so delivery took a little longer than usual, but I have no issues with the product. 263492
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: Jaime H.11/25/2016
Product is good quality, I made and error in ordering it, so I am waiting for the correct part. Service over the phone was great too! Thank you for your help in ordering the right Brake Controller Adapter. 319477
very good kit . nothing else needed .love the 7 way plug . very well made . brake controller is very good .like the ability to bench test it before install. very happy with all material and Etrailer . 238373
by: David G.07/07/2016
Product was delivered as scheduled. Easy installation and works great. E-trailer made it easy to order and provided outstanding customer service. Would recommend them for any trailer related needs. 268879
by: Edward P11/09/2015
I have yet to install this item,but,if it is as complete,reliable and easy to install as other trailer electrical hitch items I have purchased from Curt then I will be satisfied.Thanks Ed. 231637
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: John A05/26/2016
Small easy to install item. I used the adapter cable to connect to my pre wired motor home and it could not have been easier. Operating instructions share simp,e to follow. 251913
by: John A05/26/2016
Small easy to install item. I used the adapter cable to connect to my pre wired motor home and it could not have been easier. Operating instructions share simp,e to follow. 251912
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
I installed my new Curtis electric brake controller, connection cable, and 7 blade plug. Everything works great. Seamless installation with easy to follow instructions. 243684
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: Dick Lamos10/22/2016
As always -Product was delivered super fast-- Works great -Installation instructions were spot on- it was a very easy install- Thanks for the fast service-- Dick 309809
by: Anthony A09/01/2016
This is a great controller that doesn't break the bank and still performs like the 100.00 + ones...easy install and doesn't take up much room, nice and compact... 290166
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: Tim S03/04/2017
Perfect fit for my application. Curt brake controller, extra sheathed wire, breaker and pigtail! Etrailer videos are a great help for any dyi buyer. 352247
by: secret gardens09/11/2016
great product and prices we order from etrailer when they have what were looking for because of there pricing,qauility and reasonable shipping. 293518
Ask the Experts about this Curt Brake Controller
Do you have a question about this Brake Controller?
At etrailer.com we guarantee:
Highest quality brake controller for the best price.
Real product know-how.
Most detailed, accurate brake controller information available.
Information for this part was:
Installations, made easy.
Personalized service for life.
Trusted since 1946.
Info for this part was:
At etrailer.com we provide the best information available about the products we sell. We take the quality of our information seriously so that you can get the right part the first time. Let us know if anything is missing or if you have any questions.