Rabby ,very rare youll find 2 reds or 2 browncable in the switch wires ,more likley you will find black and red with the black identified with red tape or sleeve now its brown sleeve, with blue and brown wire, which if fully complient , by what your desribing and due to the fact there has been water present i think youll find that its not a wiring fault but the switch has failed due to water so replace the switch ,and all should be ok