Emergency Trailer Brake Quit Working

[AustinAir]

Hopefully someone can give me some ideas. I have to put my Airstream into an extremely tight storage space beside my house. (About 7" clearance on each side) So I purchased a Powercaster, It does the job but just barely because of grate and the fact it is a tandem axle. The power caster uses the emergency trailer brakes for braking by taping into the line. You activate the brake with a switch on the powercaster. I had pinched the line by accident when putting jack stands under trailer and had to splice a piece of wire in. The length was tight but I pulled the slack out and was able to make connection. This seemed to work for a while although I seemed the trailer would roll about 3" before it engaged. I found as I tried to put my trailer back in storage yesterday that the emergency brake quit working. I crawled under and saw I wire connection loose by the wheel and repaired. Still no emergency trailer brake either with powercaster or even when I pull the plunger on the saftey device.
Any ideas? I am at a loss and need to get my Airstream back in it is cubby whole before my Central Austin neighbors complain.
Thanks for any advice.
Andy Oliver

[azflycaster]

The break away circuit is very simple. 12 volts is applied to the brake magnets from the trailer battery when the switch is engaged. If you battery is charged you should be able to trace the line to each of the magnets. The connection from the switch should go to the back of the brake line connection where the 7 pin plugs into the trailer. The wheels need to turn to pull the magnet arms that move the brake shoes.

Since the circuit is sending a hot signal to the brake magnets, it is possible to burn the magnets if they are energized for too long a period. Anything longer then a minute or two could damage the magnets. I have never cooked a magnet, but that is what I have been told. You should be able to check the resistance to the magnets with a multi meter. Each magnet should read about 5 ohms. All 4 tied together would read less.

[AustinAir]

It appears that the 12v power wire for my emergency brake comes from the power line that runs to the electric jack for the trailer tongue. And then single wire runs to the wheels where it is joined by another and splits to go to the back of the wheels. Do I need to scrape some insulation of the wires and test? Also if I have fryed the magnets, how do I replace them and how big a job is it? Does this effect my regular electric trailer brakes? Thanks for all the help, I am new to this and have never been very handy or mechanically inclined, but a 36yr old Airstream forces you to learn quickly.
Thanks
Andy Oliver

[azflycaster]

The power to the break away switch is just as you stated. You should be able to check voltage and/or ohms where the magnets plug into the wires behind the wheels. If the magnets are cooked, you have no brakes at all. To replace the magnets, you would need to pull the brake drums. The magnets are attached to arms that ride on the inside surface of the drums.