Note: The connectors have different locks. Press the locking tab in the place marked with an arrow and pull the connector at the same time.
When ringing or measuring voltage with a measuring device, insert the tips of the device wires only from the back side of the connector (from the cable side), and not into the connector sockets, see the figure. When inserting the measuring wires into the connector sockets, the sockets are deformed, which leads to the so-called floating contact.
If you need to replace a connector terminal, insert a narrow screwdriver from the open side of the connector between the spacer tab and the terminal. Press the spacer tab and pull the connector terminal back by the wire. Insert the new terminal until it snaps into place. Pull the wire to check that the terminal is securely installed.