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

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? 101502

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. 74941

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. 74946

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. 74960

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 99084

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. 73687

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 73712

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. 73720

Reply from William K.

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

Reply from Jon G.

@WilliamK Happy to help! 73751

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. 98734

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. 73513

Reply from William K.

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



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