This is a redo of the old Clipsal Switch Multiplier, sometimes you just need to use one of these to get out of a situation with out having to cut wall and put new wires in an old house.
If you need that, you need this. It comes as a kit so you need to assemble it, but it only taked 10mins with a soldering iron at most maybe 5min if your good.
You will have access to both relays open and closed contacts and while the relays are 16A , it is designed for small loads only around 3A which is normally all you need.