Originally Posted by BMFLYFISH
I unhooked my trailer and it rolled off the cement paver I use to keep it level when it is being stored. Nothing terrible happened but it was one of those WTH moments. Originally I was told it takes an electric current to separate the pads from the drum, so I would always plug the camper in when just moving the trailer in yard. As a test, I hooked it back up without plugging it up and I can pull it or back it up with out any effort. Is this normal or is there something wrong with the brakes? The local dealer says that it takes an electric current for the brakes to work, which makes sense to me, but as I mentioned earlier, the dealer I purchased the camper from said it took a current for the brakes to separate from the drum. The brakes feel like they are working normally when it is plugged into the truck.
The brakes work off of 12 volt DC electric, and they get that from your brake controller inside your tow vehicle...... which only sends a proportional amount of 12 volt electric current to the trailers brakes when you apply brakes on your TV. This "electric current" energizes a magnet, that pushes an actuator, which is what pushed the brake shoes out when rolling.
You also have an emergency breakaway cable, that when engaged, sends 12 a full volts from the trailers battery to the brakes to activate them in case of the trailer coming disconnected from your tow vehicle.
Just having your trailer connected to the TV does not activate the brakes to the trailer. You must step on your brakes in the TV, which send a signal to the brake controller, which then sends power to the magnets in the electric brakes, which moves the actuator arm, and spreads the shoes out in the drum to brake the trailer when it's rolling.
These links may help:
How Electric Brakes Work | hitchweb