"Exhaust Fan" thermal protector or blown fuse: If the thermal protector or a fuse has been burned, then it should be replaced as soon as possible thermal protector or fuse. Power plug socket is bad wiring or paragraph: Check the power plug and socket, if there is bad situation happened, or because the wire has been broken, it should be replaced as soon as the plug or socket. Key switch is damaged: Check the key switch, if there is poor contact phenomenon, you should remove the key switch to repair it or directly replaced.