What causes a light switch to stop working but light stays on?

A light that stays on while the switch “does nothing” usually means the switch failed closed or the circuit is miswired so the light is fed constant power. It can also be a 3‑way setup where the other switch failed, a loose back‑stabbed connection at the switch, or a smart/dimmer stuck. If you smell burning, see scorch marks, or hear buzzing, treat it as urgent and call.

Quick checks:

• Try the other 3‑way switch, if present.
• Toggle the breaker once.
• Do not open the box if you’re not trained.

<br/> Updated: 2025-11-05 <br/> Need help in La Quinta, CA? Call (760) 343-7488 or book online.

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