The wiring is simple, pick a wire and attach it to the hot wire for your brakes (from the controller) the other wire gets attached to a good ground, preferably one directly from the tow vehicle.
As for replacing those pads, they look very much like older Dexter brake setups, I could be wrong about that, but I have seen them before. Any good trailer parts dealer can get you those parts. It is much easier to get them if you take them in and match them up tho. There are quite a few different manufacturers and some of them have subtle differences. I would look for them while you have them off, it will save you a lot of work and running around.
If you are heading down towards Mechanicsburg try Redneck, they should have them.
BTW - It is often cheaper to buy the backing plates and brakes as a unit rather than buying the individual parts, just something to keep in mind because if those are old the magnets are probably due to be replaced also.
The strongest reason for the people to retain the right to
keep and bear arms is, as a last resort, to protect themselves
against tyranny in government.
- Thomas Jefferson -
Personally, I carry a gun because I'm too young to die and too old to take a butt kickin'.