Ever since I moved into my house a few years ago this thing blinks either red or yellow at night. I can’t tell what it’s for. It’s connected to some wiring in my attic. Any ideas?

5. Pest or Environmental Sensors
Less commonly, specialized sensors for temperature, humidity, or pest detection may be installed in attics. These can also include small blinking lights for status updates or alerts.

What You Can Do
If you’re curious or concerned about the blinking device:

• Inspect safely: Use a flashlight and avoid touching exposed wiring.
• Look for labels: Most devices will have a manufacturer name, model number, or purpose printed somewhere.
• Check your home documentation: If the device was installed before you moved in, it may be noted in manuals, inspection reports, or previous homeowner notes.
• Consult a professional: If you’re unsure or the wiring looks unusual, an electrician or home inspector can safely identify the device and confirm it’s functioning correctly.

Bottom Line
A blinking red or yellow light in your attic is usually nothing sinister—it’s often an indicator light for detectors, sensors, or monitoring devices. However, taking the time to identify it properly ensures safety, avoids unnecessary worry, and gives peace of mind knowing your home systems are working as intended.

If you want, I can also make a quick guide of common blinking devices in attics with what their lights mean, which could help narrow it down faster. Do you want me to do that?