Flashing sensors

Why Are My Garage Door Sensors Blinking?

Garage doors keep our valued possessions safe and make our life smooth and well-timed. Nowadays, we search for convenience in every component we install in our house, and that is why most garage doors are operated automatically. While automatic doors are highly convenient and efficient, they pose a risk to the people using them if they are faulty like  One component that minimizes the risk of accidents when using an automatic garage door is the sensor.

This post will discuss what garage sensors are, a brief on how they work, causes of malfunction, light indicator signs of the malfunction, and finally, how to troubleshoot these issues.

What is a garage door sensor?

A garage door sensor is a safety component for any automatic garage door that prevents the entire structure from closing on something or someone. Initially, most garage door sensors were mechanical (worked by reversing a door on physical contact), but today, photoelectric sensors are the order of the day.

Photoelectric garage door sensors use an infrared beam to detect an object or obstruction on the garage door’s pathway. Two sensors are placed on either side of the door, about 6 inches above the ground, and aligned correctly to each other. The infrared beam they emit forms an invisible tripwire that will sense any object on the door’s closing pathway. When there is an obstruction, the opener is alerted, and the door stops closing automatically and reverses direction.

The door goes back to its original positions and can only be opened by engaging the emergency lever.

Possible causes of garage door sensors malfunction

Just like any other highly programmed component, garage door sensors can get faulty. Here are common causes of garage door sensors problems:

  • Lack of power supply- Garage door sensors are an electric component that requires a power supply to function. A power supply problem can be a power cut or faulty power cables/sockets on both or one of the sensors.
  • Dust on your lenses- If your garage is situated in a highly dusty area, the dust may pile up on your lenses, leading to a malfunction. The dust usually blocks the infrared beam emitted by the two sensors.
  • Moisture- If there is a sprinkler near your garage or you live in areas that experience heavy rainfall, moisture could accumulate on your lenses and block them from functioning correctly.
  • Misalignment- Garage door sensors will only work if they are perfectly aligned. If one sensor is moved out of place, the infrared beam will not reach the other sensor, which will render the entire system faulty.
  • General wear and tear- If you have used your garage door sensors for an extended period (at least ten years), general wear and tear may be the cause of the malfunction.

Light indicator signs for common garage door sensor problems

One of the straightforward ways to determine if your garage door sensor experiences the above problems is by checking if its exterior lights are on, off, or blinking when you try to close the garage door. Here are the general light indicators and what they mean about the working condition of the garage door sensors:

  • LED lights turned off

This is a problem with the power supply or electrical components such as wiring. Turned off LED lights may also indicate faulty sensors that perhaps need to be replaced.

  • LED lights turned on and glowing

When functioning correctly, the LED lights on garage door sensors should be glowing Green. If you observe that the LED lights glow Red, you might be dealing with misalignment problems.

  • Garage door opener flashing continuously

It is not all about the LED lights on the sensors themselves, blinking of the garage door opener can also indicate an issue with the sensors since these two components are interconnected. If the garage door opener is flashing continuously, then it is an indication that it cannot sense that the door sensors are connected or working correctly. Here, the flash will persist, and the door will not close unless the issue is fixed.


If the LEDs on the sensors are off, check if there is a power supply. If there are no issues with the power supply, you need to inspect the power outlet’s wiring and fix any disconnections. It is advisable to reach out to a professional if disconnecting and reconnecting the power supply cables does not work.

You can remedy red lights on the sensors by realigning the sensors. To do this, loosen the wingnut on the receiving and move the sensor around until the Green LED starts glowing.

For the opener’s continuous flashes, check if the sensors’ wires are disconnected from the opener and reconnect them. Also, check for misplaced staples holding the wires since if they are misplaced, they may cause the connecting wires to short. Fix them in place and check if the light blinks stops. If nothing works for you up to this stage, then you need to hire a professional to replace the entire wiring.

Additional tips

  • Wipe dust and moisture off your garage door sensors to reduce beam blockage.
  • If the sensors are aligned, and the red lights glow, replace the wires.
  • If the sensors are aligned, the power supply is checked, and the wiring tuned, but there are no lights at all, replace the sensors.

Final thoughts

I hope you’ve learned what blinking in a door sensor or door opener means and that you can now comfortably tell the underlying problem and troubleshoot it yourself or call a professional. Please note that it is hazardous to continue using the garage door when light indicators signal an issue. Don’t let garage door sensors be the source of accidents when they are supposed to protect you from the same. Act swiftly and accordingly!