Breakaway Kit Installation for Single and Dual Brake Axle Trailers

Breakaway kits are designed to bring trailers safely to a stop by activating the electric brakes should a trailer disconnect from the tow vehicle during transit. Ideally, the safety chains will prevent a trailer from disconnecting if the coupler comes off the ball. However, if the safety chains fail, the breakaway kit acts as a last line of defense against a runaway trailer. This type of safety system is required in most states for trailers weighing more than 3,000 lbs.

The following article will describe how to:

• Mount a trailer breakaway kit
• Wire the breakaway kit
  • Details Hopkins, Tekonsha, with and without a charger
• Attach to a vehicle

Before the breakaway kit installation begins, you will need:

• Breakaway kit - includes a breakaway switch and a battery contained in a mounting box
• Electric trailer brakes
• Connection to the auxiliary power wire from the tow vehicle
  • needed only if the breakaway kit has a charger

Breakaway Kit Components:

• Breakaway switch - mounted to the trailer frame and has a cable that connects to the vehicle's frame
  • If the trailer disconnects, the cable pulls a pin out of the switch, activating the trailer brakes.
• Breakaway battery box - houses a 12 volt battery and, in some models, a battery charger

Mounting the Breakaway Kit

• Locate a secure surface on the trailer to mount the breakaway kit battery box.
  • A typical position is on the inside of one of the trailer frames in the front of the trailer.
  • Self-tapping screws or U-bolts are usually included for mounting the battery box.
• Mount the breakaway switch close to the trailer coupler so the cable can be attached to the vehicle.
  • Also, mount the breakaway switch close enough to the battery box so their wires can connect.
  • A typical position is on the outside of the trailer frame between the trailer connector and the battery box.
  • NOTE: The switch is held in place with only one screw.
    • It needs to be tight but not so tight that it cannot rotate to allow the pin to be pulled out.

Wiring a Breakaway Kit

Breakaway Kit without a Built-in Charger

• Breakaway kits without battery chargers require three connections.
  • Remember to periodically remove the battery from the box to charge it, or replace it accordingly.
• Splice one of the two wires coming out of the breakaway switch into the trailer brake wire running from the trailer connector to the brakes.
• Connect the second wire coming out of the switch to the brake wire (blue) coming out of the battery box.
  • This connection will send power to the breakaway switch.
  • NOTE: Both wires on the breakaway switch are interchangeable.
• Splice the white wire coming out of the battery box into the existing ground wire (usually white) running from the trailer connector to the trailer, or screw the white wire directly to the trailer frame.

Hopkins Breakaway Kit with a Built-in Charger

• Hopkins breakaway kits with built-in chargers require four connections.
  • One connection has already been made inside the battery box.
• The following diagram shows a typical wiring configuration for a Hopkins breakaway kit with a battery charger.
  • Some other manufacturers have similar configurations, but not all wire colors are the same.
  • Consult your breakaway kit directions before installation to verify the wiring configuration.
• Splice one of the two wires coming out of the breakaway switch into the trailer brake wire running from the trailer connector to the brakes
  • See point A on the wiring diagram
• Connect the second wire coming out of the switch to the brake wire (blue) coming out of the battery box.
  • See point B on the wiring diagram
  • This connection will send power to the breakaway switch.
  • NOTE: Both wires on the breakaway switch are interchangeable.
• Splice the white wire coming out of the battery box into the existing ground wire (usually white) running from the trailer connector to the trailer, or screw the white wire directly to the trailer frame
  • See Point C
• Splice or run the 12 volt hot lead (black) coming out of the battery box into the 12 volt hot lead running from the trailer connector to the trailer
  • See Point D
  • This connection will charge the battery when the vehicle is in use.

Wiring a Tekonsha or Tow Ready Breakaway Kit with a Built-in Charger

The Six Required Connections:

1. Splice one of the two wires coming out of the breakaway switch into the trailer brake wire running from the trailer connector to the brakes.

2. Open the battery box and connect the second wire coming out of the switch to the positive post (red) on the battery.

• This connection will send power to the breakaway switch.
• NOTE: Both wires on the breakaway switch are interchangeable.

3. Connect the red wire on the charger to the positive post (red) on the battery.

• This connection charges the battery.
• There should now be two wires connected to the positive post: the second switch wire and the red charger wire.
• Connect the black wire on the charger to the negative post (black) on the battery.

4. Splice the white wire on the charger into the existing ground wire (usually white) running from the trailer connector to the trailer, or screw the white wire directly to the trailer frame.

• See point C on the wiring diagram shown above

5. Splice or run the 12 volt hot lead (black for Tekonsha, yellow for Tow Ready) on the charger into the 12 volt hot lead running from the trailer connector to the trailer.

• See point D on the wiring diagram shown above
• This connection will charge the battery when the vehicle is in use.

Attaching the Cable to the Tow Vehicle

The breakaway switch cable needs to be secured to the vehicle bumper or frame. The cable can be attached in many different ways. The two most common methods are:

Route the pin through the safety chain loops on the hitch or bumper, then through the cable loop

or

Route the pin through a tow hook, then through the cable loop

Notes:

• The cable should come straight out from the switch to attach to the vehicle
• Any angular attachment may cause breakaway switch failure
• Secure the cable on the same side of the trailer frame as you mount the breakaway switch
• Do not loop the cable over the hitch ball; the cable may bounce off while the vehicle is moving
• Before towing, test the breakaway kit by pulling the pin out of the switch to activate the brakes

Questions and Comments about this Article

Zasu 9/11/2022

The wiring diagram for the breakaway w/o a charger was useful enough that I was able to wire mine with the charger but it sure would have been nice to have that diagram included with the instructions for my type. Why include one diagram but not the other? 147844

John 3/18/2022

I’ve wired up as per instructions for breakaway system with charger. The breakaway works as it is supposed to but electric brakes do not activate when the tow vehicle breaks. In the instructions it shows a red wire coming out of the breakaway box going to the brake lights but I have no red wire. Would it be safe to assume the break light from tow vehicle should go to the blue wire therefore activating brakes? 134897

Reply from Les D. 3/21/2022

@John First, let me know what brand and model breakawy kit you are using. Next, let's start by eliminating the truck. With the trailer disconnected, hook up your volt meter to the blue braking signal wire. I have attached a link that will show you where on the truck connector to measure. voltage. The voltage should go up as the brake pedal is depressed. Next measure the voltage at the brakes. Wondering if when you connected the red wire you missed something. This red wire basically is a wire that runs from your truck battery to the breakaway battery as the power used to keep the brake away battery charged. 83115

Helpful Links

faq-wiring.aspx

Reply from John 3/21/2022

@LesD Thanks Les I’ve checked everything you mentioned and all works correctly. I’ve yet to check brake wire on tow vehicle but will today. Truck is near new and it’s a factory fitted brake controller and harness (Ram). 83132

Kevin M. 2/7/2022

Is there a breakaway kit with a UV resistant case? Or, perhaps, a cover? My horse trailer is stored outside at 4'000' elevation in the Southern California desert. I'm replacing the kit for the second time because the sunlight destroys the plastic components. Thanks. 132504

Reply from Les D. 2/7/2022

@KevinM I checked several of them and they don't even mention UV resistance -as expected. I don't have small bags or anything else rated as UV protected. Except, Adco # 290-1754 tire covers whose only job is deflecting UV rays. You could have a cover custom made from this material. 82722

Patrik 12/2/2021

Hi If I use chassis as a ground for the white cable coming out of the battery box and one cable from brakes as well do I still need to split the,,MAIN,, cable with the ground coming from the rear part where lights are and connect it to the chassis as well? or do not have to do that. Thanks Patrik 126861

Reply from Les D. 12/3/2021

I have attached a link to a page that shows the wiring schematic for the breakaway kit. The kit has three wires; white, black, and blue. You can connect these three wires to the existing trailer wires with the same function. You can connect your white to the chassis anywhere as the trailer is grounded in the same way. 82200

Helpful Links

faq-trailer-breakaway-kit-installation.aspx

Rorry 4/18/2021

I have separate wires coming from my brakes... white, black and blue. I know u need to ground the white to the trailer frame. I know I need to run 1 of the 2 breakaway wires to the battery power. My question is, I still have 2 wires, blue and black, coming from my brakes and 1 wire from my breakaway switch. What do I do? Also, in my breakaway switch there is a blue and a black. Which one goes to the battery? 112483

Reply from Jon G. 4/21/2021

I would think that white is for ground, black might go to another brake(?) and the blue would go to your breakaway battery. You will want to confirm this on your end though because not all wiring colors are the same. If you check out the diagram we have for the breakaway battery kit we have the white going to ground, the black going to the 12V power wire to charge it, and the blue going to the brake circuit for when the breakaway battery needs to activate the brakes. 78962

Jose C. 3/10/2021

Necesito conseguir la rabiza que VA en ei camion ford f150 98para conectar freno trailer I need to get the tail that VA in the truck ford f150 98 to connect the trailer brake 109773

Reply from Jon G. 3/11/2021

¿Necesita el cable flexible para el controlador de freno o el cableado en la parte trasera de su camión que se conecta a su remolque? Are you needing the pigtail for the brake controller or the wiring at the back of your truck that connects to your trailer? 77269

Warren W. 11/7/2020

I installed as instructed but my rear two wheels remain locked up. Has anyone had this problem. The battery is charged and the yellow light shows charging. 102951

Reply from Jon G. 11/9/2020

Have you checked the wiring or the adjustment for your trailer brakes? If something isn't wired correctly or you have some damaged wiring then that could explain why your brakes are still activated. If your brakes are adjusted to be really aggressive then that could also be a contributing factor as well. 75644

Jeffrey D. 9/27/2020

I have a boat trailer that does not have a breakaway switch. I would like to install one, but none of them I've seen seem to be submersible. On a boat trailer, the switch will spend time underwater, as the boat is being launched or recovered. Are any of these switches, batteries, and chargers submersible? 101502

Reply from Jon G. 9/28/2020

I'm not aware of any breakaway kits that have a submergible battery. The closest thing to what you're looking for is a kit like part # 20400 which has the box opening at the top instead of at the side. With that being said, your breakaway battery should be mounted on the tongue of your trailer so the only way that it would be submerged is if you're backing pretty much your whole trailer into the water. 74941

Reply from Jeffrey D. 9/28/2020

@JonG Thinking about it, I'm pretty sure that any breakaway kit with a submersible battery compartment would be explosive. You pretty much have to have a way for the hydrogen to vent. A top-opening box may be my best choice. 74946

Reply from Jon G. 9/28/2020

@JeffreyD Yes you would need a vent. Be sure to unplug your trailer prior to backing into the water as well. 74960

Reply from Joe 1/10/2021

@JeffreyD You could mount it on your winch tower and extend wiring. you could also mount trigger switch there and extend gable. 76280

Reply from Fank 4/7/2022

Most bost trailers have hydraulic brakes 83281

Reply from David B. 4/13/2022

Yup, most boat trailers will be hydraulic or electric over hydraulic. That said if they have a surge brake there will be a break away cable that will take the place of the electric switch. 83332

Reply from Jeffreyd 4/13/2022

@DavidB Mine may be an odd case. I have an odd boat - 37' long, only 8' beam, and only 20" draft. And it came with a custom trailer built to transport it, not to launch it. The prior owner said he'd launched from it despite that, but only in fresh water. I launched it and retrieved it, last fall, and the breakaway kit self-check says it's fine. 83336

William K. 9/16/2020

Sent you new email, didnt work. Wired like new curt diagram it sets the brakes with the breakawy battery.Something is wrong.tks 99084

Reply from Jon G. 9/17/2020

Yeah that's not good. The only time that should be happening is when the pin is pulled from the breakaway switch. Start by making sure the pin is fully seated and if it is then you'll want to check your ground connection for the breakaway switch. Make sure that it's securely connected to a clean, bare-metal surface. 73687

Reply from William K. 9/17/2020

@JonG I rewired it back so it works, but the only question I have is where does the integral battery charger get its power.I belive its the red wire from the battery box. Hooked it to AUX. Have yet to test that part.thanks 73712

Reply from Jon G. 9/18/2020

@WilliamK You are correct that it gets it's power from the 12V power at the vehicle/trailer 7-Way connector so you definitely want to make sure that is hot. Depending on your tow vehicle it might not get hot unless the ignition is on so you want to keep that in mind when you do your testing. 73720

Reply from William K. 9/18/2020

@JonG Thank you for your help, I am satified its ok. 73745

Reply from Jon G. 9/19/2020

@WilliamK Happy to help! 73751

William K. 9/8/2020

well,the Curt kit 52042 I just installed has a totally inaccurate manual,wiring diagram.It shows black,red,white from battery box,they are red white blue.Shows push to test and battery as 2 units they are one.Shows yellow wire from ptt there is none.Shows black as bat + its blue.Unknown what to do with red wire from bat - not shown assume grounded.Unknown how built in battery charger works as wiring is not accurate and confusing. Brake controller output from trailer connector is black diagram shows its blue.Diagram does NOT integrate well with 6 pin connector i used.All purchased from etrailer. 98734

Reply from Jon G. 9/11/2020

It sounds like Curt gave you the instructions for the older version of this kit with the updated box and wiring for this kit. If you look at the PDF instructions linked to the Breakaway Kit # C52042 product page you'll see the correct wiring. Red goes to 12V positive, blue goes to brake controller output, and white is ground. The black wire from the breakaway switch ties into the red wire from the battery while the blue ties into the blue. The 6-Way # H20036 that you purchased carries the brakes on the red wire and the 12V power on the black wire. 73513

Reply from William K. 9/11/2020

@JonG That looks a lot better. Will rewire as it shows. Sent Curt notification also. thanks for your help. 73535