What exactly is the problem? How do you know you don't get any power to the switch? I ask because, in testing out the breakaway switch on my 1976 31' Sovereign
, I found that, even after pulling the activator pin, the brakes wouldn't lock. I decided to take the switch apart and explore inside. I found that, over time and lack of use, the two copper and brass strips that should make contact and complete the circuit when the pin is pulled were separated, and had not enough internal spring to touch. Some bending, test fitting, cleaning, then two new rivits and a little sealant to keep it watertight and it is as good as new. Could this be your issue?
If there really is no power to your wire, and your battery is connected in the trailer and working, there could be another problem. There are circuit breakers (self resetting) just behind where you plug the umbilical cord in from your tow vehicle to the trailer (at least on mine). I had to remove the gaucho to get to (actually, not as hard as I thought it would be). After getting the cover off, I was able to inspect the breakers. (I actually thought they were fuses, from the wiring diagram). All were tight. A little rust, but the connections were all good.