Breakaway brake systems are required in most jurisdictions on trailers with a gross vehicle weight rating of over 3000 pounds. These safety brakes are designed to stop a moving trailer in the event that it becomes disunited from the tow vehicle. The breakaway switch is located on the trailer and a cable is used to connect the switch to the tow vehicle. If the vehicle and trailer are pulled apart, the cable will tug out the breakaway switch's plunger and activate the trailer's brakes using battery power. A breakaway kit will include the switch, cable and battery box.
Mount a breakaway battery box battery on the trailer where it is easily accessible for charging. In some cases, this may be in the trailers interior space, such as the front tack room of a horse trailer. On gooseneck trailers it may be located inside the frame on the underside of the gooseneck.
Mount the breakaway switch using a single screw or bolt on the side of the hitch frame near the coupling mechanism. The switch must be mounted forward enough on the frame to allow the cable to connect to the tow vehicle with enough slack available so it will not be pulled out when executing turns. Mount the switch so that the plunger is facing the tow vehicle.
Splice one of the two wires from the breakaway switch together with the trailer's electric brake feed wire, which is typically blue. The wires that come from the breakaway switch are identical and either one can be used.
Splice the switch's second wire to the blue wire from the battery box. If using a stand-alone 12-volt battery not specific to a breakaway kit, attach the wire from the breakaway switch directly to the battery's positive terminal.
Take the white ground wire coming from the battery box and either attach it to the trailer frame using a screw or splice it into the trailer's ground wire. If using a stand-alone 12-volt battery not specific to a breakaway kit, run a ground wire from the battery's negative terminal to the trailer's ground wire.
Ensure that the breakaway battery is fully charged before pulling the trailer.
