The four-way switch in the bathroom has five wires, and there should be only one live wire, but the one with electricity has four wires. What's the problem?

If this "four-switch" can normally control the work of lighting and heating in the bathroom, it should be that the live wire and the zero wire of the power cord connected to the switch are connected in reverse, that is to say, the switch is connected to one end of the zero wire, so that the live wire is connected to one end of the switch through four devices, and the zero wire becomes the public terminal, thus becoming "four wires with electricity", and once they are all connected to work, all five wires are "dead". Check where the power supply for the bathroom comes from (have you repaired a cassette or something? ), it is normal that the two lines are reversed.