I made this neon-lighted wall switch to act as a switch locator when the room is dark.

I salvaged a neon pilot light from my electronics junk pile and connected it across the two terminals of a standard wall switch (Photo 2).

• When the switch is OFF, the contacts are open and there is 120 V across the switch, so the neon lights up (Photo 1).
• When the switch is ON, the contacts are closed and there is no potential difference across the switch, so the neon turns off (Photo 3).

This provides a simple and reliable light-switch locator.

Neon pilot lights are ideal for this application:

• Designed for continuous operation
• Draw under 1 mA
• Produce virtually no heat
• Can remain on for years without issue

⚠️ Important: Make sure the indicator is neon, not incandescent.

Small incandescent lamps can draw tens to hundreds of milliamps, run warm to the touch, and are not safe to bury inside a wall switch box.

Although they can look similar, here’s how to tell them apart:

1. Glow color Neon emits an orange/reddish glow. Incandescent emits a yellow-white glow.
2. Internal structure Incandescent has a visible filament. Neon has no filament—only two metal electrodes not connected to each other.
3. Resistance test (multimeter) Incandescent shows measurable resistance. Neon reads open circuit.
4. Operating current Incandescent draws tens of milliamps or more. Neon draws under 1 mA. My meter has a 1 mA resolution and still reads zero when the neon is operating.

Photo 4 shows a neon pilot light.
Photo 5 shows an incandescent indicator lamp.