Indication light on switch lit when switch is off

Question

i have a guest toilet with a vent and a light, and a very light and sound proof door. more often than not people leave the switch on, which can work for days. This is a single switch and simultaneously activates the vent and lightbulb, and the wires in the images are the only ones that I have available in the wall.

i purchased a switch with an indication light, but i tried several variations of cable connecting and i either get the indication light on constantly, off constantly or on when the light/vent is off.

This is the way it came from the store, and the way it is wired right now.

I would really appriciate any guidance/help in making this work as intended

please also let me say that I found this question, but was unable to understand what to do, as I have TWO red wires, and the image in this post has two: Pilot light on switch comes on when light is off

Thank you very much

Answer 1

This is a "switch leg" which is why there is a blue (normally neutral) wire going to a switch. Switches don't use neutral.

Switches don't normally use power. They run on human power, and they only interrupt power to the light. So they only need 2 wires (always-live and "live when light should be on"), and have no need for neutral.

However, when a switch does something which requires power, such as be smart, or have an electronically run timer, or be lighted -- then, it needs power. Since it already has "always-live", it needs neutral. You don't have neutral. So anything that takes power at the switch isn't going to happen without a rewire. (no, you cannot use protective earth as neutral - I mean you can, but doing so can kill people. I'm glad you didn't discover that in your experiments).

Dump it. Get a mechanical timer switch.

This is a switch with a big clockwork mechanism. It takes some force to turn, but then, the run-down timer runs on that energy. So it is still a human-powered switch, with no electricity requirement, so no need for neutral.

They make different models of switch with different maximum run times - 5 minutes, 15 minutes, 30 minutes, etc. If the first one you see has an unworkable time, don't worry - they make others.

You can also get them with or without a "continuous hold" feature - where abuse or forgetfulness is an issue, you want "without".