I finished soldering the components onto my Power Switch Tail board last night. Plugged it in to the raspberry pi and the LED lit up. That works.
Then, I plugged it into an outlet. The relay is supposed to click. Nothing. Checked the output voltage with a multimeter. It was 3 volts or so. Something is stopping the electricity from getting through. Maybe I connected the relay incorrectly or I ruined it when soldering it on.
I need to spend some time troubleshooting.