The Department of Transportation mandates that trailers equipped with electric
brakes be outfitted with a breakaway system. The breakaway kit contains a battery
that activates trailer brakes if they become disconnected during highway travel,
preventing hazardous situations that would put motorists and their trailers at risk.
This kit also comes with a cable with pin that will pull on a switch to activate brakes
and release. Solder or crimp type connectors should be preferred to avoid corrosion
and short circuiting issues.
Brake Wires
The US Department of Transportation requires that trailers weighing more than 3000
lbs be equipped with a breakaway system to activate brakes in case they become
detached during highway travel and become disassociated from their towing vehicle.
A typical breakaway system contains both a battery and trickle charger to maintain
and charge its power source.
Breakaway kits typically consist of a pin pull switch connected by cable to both pin
and trailer brakes, enabling users to pull it on either switch in order to close its
circuit and activate their trailer brakes when pulled on by pin pull switch.
Splice one of the two wires coming out of your breakaway switch into the blue brake
wire running from trailer connector to brakes. Red wire should come into charge the
battery while blue powers brakes if you pull pin on switch. 14 gauge automotive
primary wire and solderless butt connectors should be used to make this connection
and all connections should be tight and clean.
Breakaway Wires
A trailer breakaway kit contains a battery which powers its electric brakes in case
the hitch suddenly disconnects from its tow vehicle. A switch features a cable
connecting one end to the vehicle and another end directly to the trailer; should this
occur, pulling on this cable activates brakes immediately by disengaging pin from
switch and pulling out cable on switch to disengage pin and activate brakes.
When a trailer breaks free, this device aims to prevent it from traveling downhill
towards its towing vehicle and hitting it head on. Furthermore, any on-board
batteries should also be connected to an isolator in case they malfunction.
Before each trip, disconnect the trailer cord from your tow vehicle and perform a
comprehensive breakdown switch test by pulling on its lanyard pin – it should be
difficult to pull out and you should hear brakes engage if successful; otherwise
reinsert and test again. Also ensure the battery in the switch is fully charged.
Charger Wires
This wire provides power to maintain and charge the trailer battery, though not
required in all systems. It should connect to both the red pin of the vehicle connector and a breakaway switch – usually via solderless butt connectors and electrical tape.
Breakaway switches use an additional 12-volt battery or the trailer’s existing one to
interrupt the circuit between brake controller and trailer brakes if an auxiliary
lanyard cable pulls out its switch-actuating pin, thus disconnecting them. Regularly
test this feature by pulling out its pin to ensure brakes engage when necessary.
Implement a ground wire from the trailer frame to the vehicle chassis using a 1/4-
inch bolt, nut, two washers, and one lockwasher. This will reduce corrosion at its terminals.
Ground Wires
Some wiring diagrams include a ground wire from the trailer battery to a junction
box as a way of avoiding backfeed from the trailer to the brake controller and
protecting it from overheating, possibly shorting out, or burning up altogether. This
can prevent backfeed from the trailer into its brake controller which in turn prevents
backfeed from the brake controller to the trailer as well as overheating or shorting-out/burning up of any part.
When attaching the wire from your battery to the switch, make sure it has a nut
fastening it to its frame. Scrape away any paint so as to expose bare metal beneath
and secure with solderless ring terminal.
If the breakaway switch pin is pushed in and not pulled, its voltage reading should
show at least 12 volts across blue wires 1 and 2, indicating that power has reached
both brake coils on the trailer frame as well as to the junction box from your tow
vehicle. It is essential that this voltage be present before disconnecting from your
tow vehicle to test with and without pulling on its switch pin pin.