How to Wire a Breakaway Switch to the Trailer Battery

Question

Question:

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

asked by: Lyle

0

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

0

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.

Answer 1

Hi Jeff! A break away switch, like the Curt Trailer Breakaway Kit #C52042, basically just completes a circuit that then powers the electric brakes. If you are removing it to relocate the switch and or trailer, you will want to completely disconnect…

view full answer...

Answer 2

In regards to the Curt Push-To-Test Trailer Breakaway Kit part #C52042, the blue wire on the breakaway switch will be run to the brake output circuit and the black wire to a constant 12 volt power source. The blue wire on the battery box will also…

view full answer...

Answer 3

To charge the battery in the Engager Trailer BreakAway Kit, #20099, you can attach the wire from the 12 volt circuit on the trailer side 7-Way (1 oclock position on the back of the trailer side 7-Way where the wires attach) to the input wire on the…

view full answer...

Answer 4

Yes, you'd be able to swap out your WF 8735 power center with the Progressive Dynamics Mighty Mini AC/DC Panel and Converter/Smart Charger #PD4045KA. This model is 45 amps versus your 35 amp WF 8735 power center and features a Charge Wizard that…

view full answer...

Answer 5

Hey Jim, to replace what you have with something that is Lithium compatible you would need the part #PD4045KA which is lithium compatible. It is also rated a little higher as well at 45 amps but it will still work great. What you have now is 11 7/8…

view full answer...

Answer 6

Hey Mason, yes the Progressive Dynamics 4000 Series Mini RV Converter w/ Charge Wizard and AC/DC Distribution Panel #PD4045KA that you referenced can work for you but like you mentioned you do need to make sure your current wiring can handle the…

view full answer...

Answer 7

No, you will not need a separate fuse to install the P3 brake controller #90195 on your 2016 Chevy Colorado with the factory tow package. The tow package wiring up under the dash that you will connect the brake controller to is already fused under…

view full answer...

Answer 8

According to Progressive Dynamics, the switch is located on the circuit board for the converter. You'll need to remove the black plastic cover to access the switch. When the switch is pushed to the rear, the charger is in Lithium Ion mode. If you…

view full answer...

Answer 9

Hey Lance, thanks for the information! I don't have just a lithium compatible replacement converter for your WFCO 8735. The best solution I have is the Progressive Dynamics Mini Panel item #PD4045KA. This 45 amp panel will replace everything you…

view full answer...

Answer 10

According to the installation instructions, which I have linked for you below, the Progressive Dynamics Mighty Mini AC/DC Panel and Converter/Smart Charger #PD4045KA approves the following breakers: - Thomas & Betts – TB & TBBD series -…

view full answer...

Answer 11

Hello Troy, thanks for reaching out. The current version of the Progressive Dynamics #PD4045KA is compatible with Lithium batteries. You just need to make sure the output mode switch is set to LI for lithium batteries. That will change the output to…

view full answer...

Answer 12

Based on your manual indicating 7" brakes it is probably a 2,000 lb axle. That should be a 4-bolt brake flange on the axle as well. Try checking your axle tag to see if you can verify this. The capacity may be listed, or it can be found with the…

view full answer...

How to Wire a Breakaway Switch to the Trailer Battery

Products Featured in This Question

Featured Help Information

Miscellaneous Media

Continue Researching