Can a Breakaway Switch be Wired Directly to the Trailer Battery Rather Than the Breakaway Battery

Updated 01/31/2014 | Published 01/28/2014

Question:

I have an Aliner popup with an onboard battery and I prefer to use it rather than a dedicated brake battery and charger. I see in another answer that the the 3 wire Hopkins switch can be used by wiring to my blue brake wire, the battery on the trailer and to a ground. I have a two wire switch and wonder if it can be used by connecting to the positive terminal of the trailer battery with one lead and connecting the other lead directly to the blue brake wire? My concern is that if the breakaway switch closed and the trailer connector was still attached would it back feed battery current though the blue wire to the brake controller and destroy it? Ill buy the three wire unit if necessary. Thanks.

asked by: Dennis C

Expert Reply:

All breakaway switches are designed to be wired to the positive terminal of a 12 volt battery and to the vehicles electric brake circuit. The switch can be wired to your trailer battery if you did not want to purchase a separate breakaway battery.

The Hopkins LED Breakaway Switch, # HM20060, has three wires because it has an LED light in the switch. The ground is for the LED light, not the brake switch. When the pin is pulled, power would still be fed to the electric brake circuit. The breakaway switch that you have will work the same as the Hopkins LED switch. The only difference would be the LED light.

There is always a possibility that back feeding could affect the brake controller, but it is not very common. Many newer brake controllers have built in protection to help prevent power back feed from damaging the controller, but, again, there is always a chance the brake controller could be affected. Unfortunately, this would be the case with any breakaway switch or breakaway kit out there.

expert reply by: John H