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Brake Buddy Select 3 Portable Supplemental Braking System - Proportional

Brake Buddy Select 3 Portable Supplemental Braking System - Proportional

Item # HM39524
Our Price: $1,410.05
You Save: $551.94
Tow Bar Braking Systems

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Get intense, emergency braking or steady, smooth braking in a single portable system. Easily switch between proportional or full braking. One-touch Auto Start makes setup fast and easy. Remote lets you change settings from your RV. Great Prices for the best tow bar braking systems from Brake Buddy. Brake Buddy Select 3 Portable Supplemental Braking System - Proportional part number HM39524 can be ordered online at or call 1-800-940-8924 for expert service.
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Brake Buddy Tow Bar Braking Systems - HM39524

  • Brake Systems
  • Air Brakes
  • Air Over Hydraulic Brakes
  • Hydraulic Brakes
  • Proportional System
  • Brake Buddy
  • Portable System
  • Recurring Set-Up

Get intense, emergency braking or steady, smooth braking in a single portable system. Easily switch between proportional or full braking. One-touch Auto Start makes setup fast and easy. Remote lets you change settings from your RV.


  • Supplemental braking system applies towed vehicle's brakes in proportion to braking action of RV
    • Responds to deceleration of RV to activate towed car's brake pedal with matching intensity
  • Full-braking setting activates brakes in towed car with maximum power no matter how you apply the brakes in the RV
  • Braking power settings ensure that the system applies your car's brakes with the correct pressure
    • Eliminates over-braking and the damage it can cause
  • Sensitivity control lets you adjust rate of responsiveness of internal sensor
    • Low sensitivity requires intense stopping action from RV to activate brakes in towed car
    • High sensitivity allows Brake Buddy to respond to even minimal slowing of RV
  • Advanced terrain-sensing ability prevents false braking
    • System won't activate when going over bumps
  • Wireless remote control mounts in cab of RV
    • Plug into 12V accessory outlet or use with AA batteries
    • Easily check readouts for potential problems
    • Change braking modes and settings while on the go
  • Lightweight, portable system is easy to position, adjust, and remove
    • TruFit risers allow unit to sit level for optimal performance
    • Quick-Lock clevis is simple to install on almost any car's brake pedal
  • Easy-Pull harness provides power and breakaway connection
  • 15-Amp charger charges your towed car's battery while you tow
  • 1-Touch Auto Start sequence prepares braking system with a push of a button
    • Removes excess vacuum pressure from your car's brakes
    • Checks braking system for errors
  • Compatible with hybrids and other cars with electric power-assist brakes


  • Dimensions: 19" long x 11-3/4" wide x 6-3/4" tall
  • Power draw at 12V: 15 amps
  • TruFit riser adjustment range: 1" - 4" tall
  • Easy-Pull harness length: 36"
  • Weight: 12 lbs
  • 5-Year limited warranty

Note: Removing your vehicle's floor mat before installation is recommended.

Proportional Braking

The Brake Buddy Select 3 is a proportional braking system that applies your towed car's brakes with an intensity that matches your RV's braking action. The built-in inertia sensor detects when and how your rig slows down, and it then engages the actuator arm to press your car's brake pedal with an intensity that matches that slowing action.

The main unit of the Brake Buddy Select 3 is designed to activate only when deceleration is actually taking place. It is built with advanced terrain-sensing technology that keeps the unit from activating when you go over bumps in the road. As a result, your towed car's brakes won't engage unless you intend for them to engage.

Full Braking

You can also select the full-braking mode. When in this mode, the Brake Buddy will activate your towed car's brakes at the maximum preset intensity, regardless of how intensely your RV is decelerating. The full-braking setting is ideal for when you're towing a heavy truck or SUV, or if you're towing your car down a steep incline. By setting the power to a higher level, you can ensure that the momentum of your towed car won't cause it to push against your RV.

Braking Power Settings

Select Control Panel

The braking power settings determine how intensely the Brake Buddy Select 3 applies your towed car's brakes. When you're first setting up the Brake Buddy, choose a braking power based on your vehicle type. Begin with a pressure that falls into the recommended range for your towed car, as seen on the chart below.

Vehicle TypeRecommended Braking Power
Hybrids10 - 20 psi
Cars and Compact SUVs25 - 45 psi
Small Crossovers25 - 45 psi
Crossovers and Small SUVs35 - 65 psi
Mid-Size Pickups35 - 65 psi
Large SUVs and Pickups45 - 75 psi

After selecting an initial setting, press the plus or minus buttons on the actuator unit's control panel to fine-tune the power setting. The setting should be enough to cause your towed car to give a slight tug at your RV during a braking event. Braking power doesn't normally need to be reset unless you're changing to a different towed car.

Once the overall braking power is set, you can customize the sensitivity on the Brake Buddy. The sensitivity setting determines how aggressively you need to brake in the RV for the Brake Buddy to activate your towed car's brakes. If you set the sensitivity high, then your car's brakes will activate with just a light tap of your RV's brakes. Setting the sensitivity low ensures that your car's brakes will only activate when you hit the brakes in your RV with a fair amount of intensity.

Easy Remote Operation

Select Remote

The included remote control allows you to monitor or change settings for the Brake Buddy Select 3 from the comfort of your RV's cab. You can easily switch from proportional braking to full braking and vice versa with the push of a button. You can also change the Brake Buddy's sensitivity settings, which makes it easy to fine-tune the braking as you drive so that you can adjust based on feel. Finally, the remote will illuminate to alert you of any errors with the Brake Buddy system, including a breakaway event.

Powering the Brake Buddy

Instead of connecting to a 12V accessory outlet, the Brake Buddy Select 3 draws power directly from your towed car's battery. To do this, the included wiring harness connects to your car's battery. Install the harness by routing the wire end through your car's firewall and into your engine compartment. Connect the harness to your battery with the included battery wire and ring terminal.

Mount the connector that's on the opposite end of the harness in a convenient, out-of-the-way location beneath your car's dash.

Easy-Pull Harness

To connect the actuator unit to this connector, use the included Easy-Pull harness. This harness plugs into the connector below your dash, then into the braking system. When connected, the harness carries both power and breakaway functions in a single cord. And the large grip ring and wide handle make it easy to hold while connecting and disconnecting the actuator, all without ripping connectors or pulling on wires.

If you're concerned about your car's battery going dead as you tow, don't worry. The Brake Buddy Select 3 includes a 15-amp charger that pulls power from your RV to keep your car's battery charged while the Brake Buddy is connected.

Fast Setup and Universal Design

Not every car is built the same. Some have brake pedals with unusual shapes. Some have uneven floorboards or mats. These differences can make it difficult to set up a portable braking system in your towed car. But the Brake Buddy Select 3 is able to fit in almost any car on the market.

Quick-Lock Clevis

The Brake Buddy's actuator arm comes with an adjustable Quick-Lock clevis, which securely wraps around your towed car's brake pedal, regardless of the pedal's size or shape.

The clevis also comes with a quick-locking lever. Once you adjust the jaws of the clevis to fit your brake pedal, turn the lever to tighten the clevis in place. And when you're done towing, disconnecting the clevis is a snap. Just turn the lever to release the clevis jaws, and remove the clevis from your brake pedal. It's that simple.

Risers Off Kilter

Uneven floorboards can cause a portable braking system to sit at an angle in your towed car. This affects the leverage of the actuating arm, which can result in ineffective braking. Each of the TruFit risers on the Brake Buddy Select 3 actuator unit can be individually adjusted, raising or lowering each corner of the actuator unit, so that the system sits level in your car. As a result, the actuator arm is able to press straight against the brake pedal to ensure that your brakes are properly depressed every time.

TruFit Risers with Wrench

To adjust the height of the risers, twist them counterclockwise, either by hand or with the included riser wrench. Pull each riser out to match the height you need, then twist the riser clockwise to secure it at that height.

One-Touch Auto Start

Select AutoStart

The Brake Buddy Select 3 will automatically check your brakes every time you start it up to confirm that your vehicle is ready to tow. After setting up the unit in your towed car, press the Auto Start button on the unit's control panel. The arm of the unit will push and release the brake pedal several times, removing vacuum pressure from the brakes to prevent overbraking. The unit will also check for any connection errors.

39524 Break Buddy Select Three Portable Towed Vehicle Braking System by Hopkins

Installation Details HM39524 Installation instructions

This Product Fits The Following Vehicles

California residents: click here

Customer Satisfaction Score:

Customer Reviews

Brake Buddy Select 3 Portable Supplemental Braking System - Proportional - HM39524

Average Customer Rating:  4.5 out of 5 stars   (250 Customer Reviews)

Get intense, emergency braking or steady, smooth braking in a single portable system. Easily switch between proportional or full braking. One-touch Auto Start makes setup fast and easy. Remote lets you change settings from your RV.


The proportional breaking never worked right and on our last trip the system kept cutting out until it quit working all together. I was in the southern US and had to drive back to Canada without the aid of the breaking system. i tried to check it out and fix it but was unable to get continuous power to the brake buddy.


Don't really like this system and decided to just tow without a braking system at all and all is good by doing so. This unit is awkward, expensive and a pain to use

Etrailer Expert

Katrina D.


I would definitely look into your states laws on pulling a trailer with or without a braking system. For instance, in Missouri, by law a supplemental braking system is not required except on trailers coupled by a 5th-wheel and kingpin. While in Idaho the law states "Trailers with an unloaded weight of 1,500 lbs. must have an independent braking system, and a breakaway system." Please double check your states laws before proceeding without a braking system.

Jeep Liberty

I have had the brake buddy system 3 for a year and it's a great braking system, I have no problems and its works great with my jeep liberty.


Overall good performance so far with the Brake Buddy. The only issue that we had was the cable connected to the unit would come loose during operation and send a “check Brake Buddy” error on our remote. We were able to easily remedy this by using a screwdriver to spread out the connection terminal to make it tighter as per customer service instructions.
Customer service is great & very helpful!


Plug keeps getting loose on unit. I drilled a hole in the case and installed a tie wrap attaching wire to case no more movement of plug works great otherwise


Nice unit, does what it is supposed to do and will noticeably slow my towed vehicle. It is a little cumbersome, but I set everything up in 8 or so minutes. Downside is that after one month long trip it would lose power after hitting a bump. Customer service was great and I eventually sent it back for repairs. They replaced a few things and has worked well until very recently. It appears that the plug will lose contact for a second over a bump and then the unit goes into a standby mode. The remote will let me know and I have to pull over and rebleed the unit. Some dielectric grease seems to have solved the problem

2020 Jeep Wrangler

If you’re installing in a 2 door Jeep this brake buddy will install much easier if you 1. Remove floor mat 2. Set the driver seat all the way back towards the rear and 3. Lower the driver seat all the way down. By doing this the brake buddy will fit properly and allow for installing the cotter pin into the cleaver.

Jeep Wrangler

I looked at several supplemental braking units and wanted one that was portable with nice features like wireless monitoring and parameter changes while flat towing my Jeep Wrangler. I reviewed the videos on the etrailer site for features and installation instructions, they’re well done and really helped with my buy decision and installation guidance. I decided on the Select 3 mainly because of the option for full or proportional braking, as I live in CA and take my RV through mountain passes often. The installation was straight forward with the help of the etrailer videos, very well done. The initial testing of the unit was a bit tricky, but it worked, after leveling the unit out. The first trip with the unit was from Southern CA to Paso Robles through the “Grapevine” pass and some other large hills, the unit worked well and gave me the extra braking I needed while flat towing my jeep behind my RV. During this trip, the unit was inconsistent in bleeding the brakes upon startup. I shared this information with etrailer in detail, and they sent me a replacement unit after trouble shooting. I want to thank etrailer for excellent support of a product which I entrust the safety of my family to while in use. The new unit has been wonderful on two other trips so far. I’m very happy with the performance and ease of use for the Select 3. It just takes a few minutes to position in the jeep, activate and get going down the road after the initial install was complete, which only took a few hours to run simple wiring. The unit is not very large or heavy, and easily fits in a normal storage compartment of the RV when we arrive at our destination. I look forward to many more trips with my family in our RV and the Select 3 giving us the supplement braking we need in our jeep on any road type.


Had to remove weathertec floor mat and lamb wool cover from seat for proper fit. Company was very responsive in helping me with the fit to our CRV. Unit function very nice with smooth application of toad braking. Remote display is compact and clearly shows when unit is working. Quite happy with my Break Buddy.


Easy to get the car ready for towing. Just a few minutes. The permanent wiring with a battery tender makes towing worry free.


Much Better than Air Braking. This system can be setup in one minute. I also have another vehicle that I use it with after purchasing an additional wiring kit. It’s easy and it works well. The wireless monitoring is flawless from the driver seat in my 38 foot Monaco Diplomat.

2014 Jeep Wrangler

This was super easy to install in my Jeep. The install video for the Wrangler was spot an very helpful. I installed a permanent brake system in another car before doing this one and I am so pleased with the install.

Now I am off to test it out.

Trevor B.


Ive been using this for a year now and have set it up a couple dozen times or more. This was so much easier than an installed brakes system. The only issue that weve had with it has to do with the power cable that connects to the 4 pin connector inside the vehicle. After some time the connector gets loose enough to fall out which requires is to pull over and reset the system. From Brake Buddy the fix is to look at the pins on the cable and where the tips of the pins almost look like you could a screwdriver, use a pocket knife or something thin enough to fit into the slots and gently spread them apart. I definitely recommend this device for a good, simple brake system.

Etrailer Expert

Mike L.


@TrevorB They gave you great advice, that's exactly what we recommend to folks that have the same problem with their # HM39524 Hopkins Brake Buddy.


This unit is large and hard to install each time in my Honda CRV

It works great when installed



Just OK - doesnt fit well in my Honda CRV - Awkward set up each time. Seems to work well


I’ve towed close to eight thousand miles in the past year. I had an incident when someone thought it amusing to pull my hitch pin while I pumped gas. The hitch dropped off about a half mile later and my break buddy saved me from any serious damage. Just got home today from a 3600 mile trip and no problem.



I had to replace the release pin on my tow hitch but with good tech support it was relatively easy. Had an incident with the brake buddy which caused the breaks on my toad to overheat. I don’t believe it was the device but rather the way I had installed it that caused the issue.since repairs. I have towed about 2500 miles without incident.

2019 GMC Acadia

So far so good! Haven't towed yet, but installation and test was successful. Install directions leave a little to be desired, all of the wires on the wiring diagram are black some have a color listed next to them some don't, it would have been a guessing game if it wasn't for the videos I found on etrailer. Upon initial test of the system, it went through its 5 actuations, indicated "normal" but kept the brake depressed, I double checked all the wiring, redid some iffy connectors, next test was the same, 5 actuations then an "error" light. Unplugged the system and waited 5 min, then performed test again. It tested well, showed "normal" but kept the brake depressed. I began to suspect the brake away switch. I repeated the pin with no luck, removed the whole assembly and the brake released. I found there was a factory splice point about 6 inches from the switch, I redid thoes connections and the system works as advertised!!
Thank you etrailer for the recommendation. Will update once I hit the road



Over the past year I have put about 10K miles on this unit, and it has been Flawless, up until this last trip. During A short 100-mile trip in January, I kept receiving the Check Brake Buddy Unit light. When checking the unit I found it would be powered off. After the 3rd time I disconnected the vehicle and drove it the rest of the trip. After some troubleshooting, I found the power cord at the Brake buddy unit to be intermittent. In order for the unit to work properly I have to apply a slight upward pressure on the power cord, once the pressure is released the unit loses power and turns off. I currently have to run some string through the thumb hole up to the steering wheel and tie it to maintain power, even then a large bump will turn the unit off. When the system works, its amazing, when it doesnt its very frustrating

Etrailer Expert

Heather A.


Hey James, this is actually a known design flaw with the power cord of Brake Buddies. It has since been fixed but Hopkins will help you out if you contact them. I will send you the deets.


Hi Miranda, here are the pictures of the bracket and Brake Buddy installed in my Jeep. Works very well. I tried to move the seat forward a bit but when the Brake Buddy activated it pushed the seat adjuster and moved the seat all the way back. Thank you for the bracket.

2020 Jeep Wrangler

Just returned from our first camping trip with our Wrangler in tow. The Brake Buddy worked flawlessly and gave me the piece of mind I needed to safely tow a vehicle behind our RV! Takes some time to get it installed and adjusted the first time and then is an absolute breeze to install subsequent times. A great product!


BrakeBuddy is a great product. I had verified this newer style included a 12 volt plug. It does, but there is no where to plug it in according to their manufacturer, Hopkins. I will need to rewire two tow vehicles before I can verify that this item works. The box was delivered and dropped off on my driveway without a signature for a $1300 item!!! Also, the box was not even taped shut. I have verified that all the parts are present.

Etrailer Expert

Thomas M.


Instead of connecting to a 12V accessory outlet, the Brake Buddy 3 draws power directly from your towed cars battery. To do this, the included wiring harness connects to your cars battery. Install the harness by routing the wire end through your cars firewall and into your engine compartment. Connect the harness to your battery with the included battery wire and ring terminal. Mount the connector thats on the opposite end of the harness in a convenient, out-of-the-way location beneath your cars dash.



Having rewired two vehicles to use the new BrakeBuddy my husband and I had an RV trip with friends to four wheel around the Anza Borrego State Park in California. The BrakeBuddy performed flawlessly on the trip down there in our 4 wheel drive truck. Setting up to come back it would not power up. We discovered that the inline fuse was blown, replaced it and home we went. The RV needed some maintenance so we hooked up our hybrid car, setup with the new BrakeBuddy, and delivered the RV to the shop. When we went to pick up the RV, the BrakeBuddy would not power up hummm. Again, we found a blown in line fuse, replaced it and headed home. I contacted Hopkins Manufacturing about this. They thought the problem might be in the unit and requested that I send it to them. They kindly offered a prepaid mailing label. They found a short in the wiring and the unit was back to me within a week. This is my second BrakeBuddy and I was quite happy with Hopkins service on our first unit which we used for over 15 years. We only purchased a newer model because of the hybrid vehicle.

Dodge Charger

I had to set the height up to miss the seat release and the driveshaft release. I do not have it braking the toad yet so the review might be premature. No one explained how this works. It does not connect up the the brake light but rather uses slow down sensing. Also, matching the wire colors would have been nicer (breakaway switch has black and red wires but they are connected to the brown and red on the brake buddy loom. The black wire was power and was to be connected to the red wire which was connected to the battery. The fused wire for power had a ring connector just 3 inches from the fuse so you could not mount the power fuse as configured. I wanted to mount the two fuses and the battery charger on the fender well so had to do some cutting.

2017 Jeep Wrangler Unlimited

Peace of mind! That's what this gives me. We have towed several times with it now and it's an ease to set up. The first time took a little longer, as to be expected, but now that everything is set where we need it is so easy to drop in and hook up.

2010 Honda CR-V

I have owned an older Brake Buddy Classic model for about 18 years. I wanted to update to the Select 3 and found the eTrailer price to be the best deal. Very pleased with the install of the select 3 and its improved functionality. Fits tight in my 2010 Honda CRV but workable. Looking forward to our first trip using the new Select 3.


I've used this in a 2022 Chevy Colorado ZR2 - towed behind a 2016 Thor Axis. The unit works as expected, but after 5000 miles of towing (Over 2 months) one of the connectors seemed to lose it's tight fit. When hitting a bump in the road, they system would disengage due to the connector wiggling loose ever so slightly. I'd have to pull over and push it back in. This continued to happen until I utilized duct tape - the master fix-it item.)


Brake buddy works well,our brake pedal is small and the fit doesn’t work,they sent a adaptor it is ok


Install went very well. Instructions were spot on.
Very pleased with results.
Will be ordering more items to improve stability and control on my Class C.


The price from etrailer was good on this brake kit. Arrived very quickly. The box tge brake kit came in was thrashed had what looked like road rash and it had been opened. I don’t know if it was shipped in that condition or did ups do that.
Does make me a lil concerned when you’re dealing with a kit like this. But the brake has a 5 yr warranty

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