Hello dear @elmundodexao.
I liked this second post. Congratz!
I have a little anecdote to share:
so we must verify that it is in the correct position; 0 is off and 1 is on.
It's not really a "zero", nor is it a "number one" or a "letter I".
These two characters that we see are to indicate if the circuit is "closed" (O) or "open" (I).
That character that we can interpret as a "zero" is actually a "circle" that symbolizes the closed electrical circuit.
I just wanted to share this curiosity with you.
This source checking method is actually what I call the "Mc.Giver method".
Over time I could realize that it is always better to have a power source tester since we could more accurately detect the type of failure that it presents and in which of the voltages is where the deficiency would be.
Cheers!