How Do Garage Door Sensors Work?

If you have an automatic garage door, you have garage door sensors. Still, most people don’t understand how garage door safety sensors work. You should have a thorough grasp of the process to ensure yours work correctly and don’t put anyone in your home in danger. If you haven’t checked these safety tools before, we compiled this overview of how to test garage door sensors to help make sure your door works correctly. 

What Are Garage Door Sensors?

Door sensors are a safety feature that became mandatory for garage doors in the 1990s. The sensors prevent the garage door from closing if there is something beneath it. 

How Do Garage Door Sensors Work?

Sensors come in pairs, one for each side of the garage. They each have an eye, and those eyes face each other. Each eye must be able to “see” the other to signal the door to close. If they cannot send that signal, then your garage door will stop closing and reverse its motion to open again. If your door refuses to close, your sensors may have stopped functioning. 

How to Check If Your Garage Door Safety Sensors Work

Can garage door sensors stop working? Yes. Here’s how to tell if a garage door sensor is bad: 

  • Open your garage door. Place a box between the two safety sensors, about in the middle of the doorway, that is higher than both eyes. You want to disrupt the eyes’ abilities to “see” each other. 
  • Hit the button to close the garage door. It should stop going down immediately and return back up.
  • If the garage door does continue to go down and then crushes the box, something is wrong. Look over the two sensors. Is a light on one of them blinking? Then your sensors are misaligned. Tighten the screw near the light to return it to the correct position. If the sensor looks as though it’s bent, straighten it out to its original position. Reopen the garage door. 
  • Get another box and try closing the door again. If it closes a second time despite your adjustments, use a soft cloth to wipe off dirt and debris on the sensors, which may be interfering with function. Reopen the garage door. 
  • Put another box in the middle of the sensors and try the door again. If it closes, check the area around the sensors. You may have kids’ sports equipment or other stored items blocking the beam. Look for signs the sensors have been exposed to water, such as from a rainstorm, which may compromise their utility. 

If you perform the test again and the box gets crushed once more, it’s a safe assumption your sensors are broken. 

How Long Do Garage Door Sensors Last?

Sensors that are well-maintained can last for many years. If you perform no maintenance on them, such as clearing them of debris and tightening screws, they will wear out more quickly. 

Now that you understand how to check if your garage door sensors are aligned, you can tell if you have a bad sensor or you just need to adjust their positioning. If moving and cleaning them doesn’t work, Quality Overhead Door can repair your sensors or install new ones to help keep your family and your property safe. Get the help you need by scheduling a service or contacting us for more information. 


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