How do you wire electric brakes at the travel trailer brake drum?

How do you wire electric brakes at the travel trailer brake drum?
It depends on the axel and brake manufacturer, but must of the wires on the magnet do not have polarity. They work like a common resistor. One wire will connect to power and the other to a ground. It is Dexter's recommendation that a common ground be run from the the trailer plug to the brake magnets. Do not ground each brake individually to the trailer frame or structure. Also note that the brakes should be wired in parallel, not in series.

So, simply, you run the wires from your electric brake controller (You do have one, right?) through your trailer light jack, to your chosen "positive" side, and back again through your chosen ground, through the trailer light jack again. Some states require the use of a breakaway switch. What you would do in that case is add a "breakaway switch" in between the trailer battery (obviously it has to be on the trailer.) and the "positive" of the electric circuit, and the negative will also have to go through the battery/chassis ground. the switch cable is connected to the tow vehicle somewhere other than the hitch! This way if the trailer hitch fails catastrophically, the breakaway switch applied full breaking force to the trailer, trying to prevent it from rolling through a minivan full of kids.

If none of this makes sense, you should take a good look at automotive electrics first. This is really dangerous, and you has a potential to cause severe, (totalling) damage you, your trailer, and everyone around you if you don't do it right. Make sure you follow all accepted trade practices and good work techniques. Test EVERYTHING vigorously before you take it out on the highway. It's also a very simple job, so, do it, but be careful.

You should also look at the axel manufacturers website and documentation. they are full of good advice, Dexter's for example, can be found at http://www.dexteraxle.com/products___literature