bing tracking image

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:

The battery box has been mounted to the inside of the trailer frame, adjacent to the trailer connector plug.

Before the breakaway kit installation begins, you will need:

Breakaway Kit Components:

The breakaway switch has been mounted towards the front of the trailer frame, between the rear of the vehicle and the battery box.

Mounting the Breakaway Kit

Hopkins Diagram

Wiring a Breakaway Kit

Breakaway Kit without a Built-in Charger

The first switch wire has been spliced into the blue trailer feed wire.

Hopkins Breakaway Kit with a Built-in Charger

The white wire from the battery charger has been grounded to the trailer frame.

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

The Six Required Connections:

The first switch wire has been spliced into the blue trailer feed wire.

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.

The second switch wire has been connected to the positive red post on the battery.

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

The red and black wires from the charger have been connected to battery.

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

The white wire from the battery charger has been grounded to the trailer frame.

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.

The 12 volt hot lead wire from the charger has been spliced into the trailer 12 volt hot lead.

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.

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:

The cable pin has been pulled out of the breakaway switch, activating the trailer brakes. The cable pin is passing through the safety chain pocket and the cable loop on its way back to the switch.

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


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


Questions and Comments about this Article

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?
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?
Etrailer Expert
Reply from Les D.

@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.

Reply from John

@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).

Kevin M.
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.
Etrailer Expert
Reply from Les D.

@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.

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
Etrailer Expert
Reply from Les D.

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.

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?
Etrailer Expert
Reply from Jon G.

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.

Jose C.
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
Etrailer Expert
Reply from Jon G.

¿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?

Warren W.
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.
Etrailer Expert
Reply from Jon G.

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.

Jeffrey D.
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?
Etrailer Expert
Reply from Jon G.

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.

Reply from Jeffrey D.

@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.

Etrailer Expert
Reply from Jon G.

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

Reply from Joe

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

Reply from Fank

Most bost trailers have hydraulic brakes

Etrailer Expert
Reply from David B.

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.

Reply from Jeffreyd

@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.

William K.
Sent you new email, didnt work. Wired like new curt diagram it sets the brakes with the breakawy battery.Something is wrong.tks
Etrailer Expert
Reply from Jon G.

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.

Reply from William K.

@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

Etrailer Expert
Reply from Jon G.

@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.

Reply from William K.

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

Etrailer Expert
Reply from Jon G.

@WilliamK Happy to help!

William K.
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.
Etrailer Expert
Reply from Jon G.

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.

Reply from William K.

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



Sports and Recreation

Trailer Parts


What our customers are saying:

"Very helpful/friendly Customer Service. Competitive Pricing. Shipping was Fast."

Mankato, MN

Popular Vehicles