How to Wire a Breakaway Switch to the Trailer Battery

Updated 06/23/2025 | Published 06/19/2018

Products Featured in This Question

Replacement Breakaway Switch for Bright Way Trailer Breakaway Kits

(178)

$25.53

Question:

How do you wire a break away switch to your trailers battery without using a break away box?

asked by: Lyle

Expert Reply:

In order to install a two wire breakaway switch like the Replacement Breakaway Switch with Cable and Pin part # 3802348 to an existing trailer battery you will want to attach one of the wires to the brake output signal (usually blue) on the trailer and the other wire to the trailer battery. The wires are non-polarized so it doesn't matter which wire is attached to battery/brake output signal.

However, most states require that the breakaway switch be wired to a separate independent battery on the trailer and not the one used for other functions such as appliances or lights. Therefore, it may just be better to replace the entire system with something like the Hopkins Engager Push-To-Test Trailer Breakaway Kit part # 20099 which comes with an independent battery specifically for the breakaway switch.

I have attached an install/review video of this kit for you as well.

expert reply by: Conner L

click to enlarge

Saul H.

6/21/2025

Hi Conner, I am installing a fast way breakaway switch to my tent trailer. It has a 7 way pin that charges the battery while being towed. My ? is since the two wires are not polarized, one is connected to the blue brake wire and the other is connected to either wire that is connected to the trailer battery. I know I have to disconnect the 7 pin when not towing or both batteries will be drained. Am I correct? Thanks

Jerred H.

6/23/2025

@SaulH No, you don't need to disconnect anything while you're not towing your trailer. You vehicle is going to automatically turn off of all power to the 7-way connector after it's been turned off. There's only draw on the brake controller wire when your vehicle is activating the brakes. The accessory circuit that charges your battery will be inactive once the power to the 7-way is turned off by your vehicle.