If you read the Q&A section on Amazon there are instructions for connecting the switch.
Replace "light" with "voltage regulator"Gabe G. said:Red(load) goes to the positive + wire of the light. The white goes to the negative terminal of the battery and the black goes to the positive terminal of the battery. Don't forget to take the negative wire of the light to the negative terminal of the battery as well.
The Black photocell wire should connect to the Battery Positive (+)Today... I tested without the buck-converter. Although I had 12+-volts into the photocell... No output from the photocell with/without sunlight.