Will Trailer Break Away System Show Power On Blue Wire With Trailer Unplugged

Updated 08/25/2021 | Published 08/21/2021

Question:

Soft-Trac 2 Breakaway Kit With Charger 52028 I used this kit to replace a very rusty breakaway system on a 2 axle equipment trailer. My question is shouldnt there be 12 volts on the blue or black wire with the trailer not connected to my truck? Where does the power come from if the breakaway switch is pulled?

asked by: Kent O

Expert Reply:

The breakaway system uses a normally open switch, so power won't be delivered to the trailer brakes unless the switch is pulled. The power is delivered by an on-board battery. You'll only see power on the wire from the switch to the battery, not on the other leg of the switch unless the pin has been pulled which closes the circuit from the battery to the trailer brakes. With the trailer unplugged from the tow vehicle, you won't see any power on the black wire which is used to receive a trickle charge for the break away battery.

I've linked to a help article that explains how trailer break away systems work.

expert reply by: Mike L