1. First, prepare a multimeter.

2. Turn on the power supply of the multimeter and turn the multimeter to the on-off test file. At this time, the multimeter shows 000.

3. After a while, the test multimeter displays 1, indicating that the test probe is disconnected.

4. Put the pointer of the multimeter, one on the incoming terminal of the switch terminal and the other on the outgoing terminal of the switch terminal. If it shows 0, it means that the two terminals are normally closed.

5. At this point, we keep the terminal fixed and lightly press the microswitch. At this time, we observed that the general indicator changed to 1, indicating that the switch connected the line and the switch was normal.