[Al Skierkiewicz]

Josh,
With this particular type of solder device, you must be careful to heat both the wire and the solder terminal before adding solder to the joint. Also be sure that the wire is tightly wound around the terminal before soldering. A good soldered connection is a good mechanical connection first.
If you first wire this up for a sensor and it would be more convenient for your programming to reverse it's operation just switch the wires on terminals 1 & 3.