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How Do Garage Door Sensors Work? (Plus Solutions to Common Problems)

How Do Garage Door Sensors Work? (Plus Solutions to Common Problems)
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Garage doors are one of the most important outdoor features, a blend of form and function that can help set the tone for your entire exterior décor scheme. Your garage door is one of the first things people are going to see when they arrive at your home, and so its aesthetic importance should not be underestimated.

That being said, garage doors are function first features, which means they must open and close easily and securely.

Anyone who has ever had to struggle with a heavy or cumbersome rolling garage door knows how difficult it can be, and has to wonder if there’s a better way. Thankfully, with garage door openers, there are. All you have to do is push a button and the garage door will open or close.

Simple, right?

Well, not always.

Those garage door openers rely on sensors to work, and that’s often where the problems arise. If those sensors malfunction or are somehow obstructed, it can cause serious problems. It might stop them from working, meaning you’ll have to go back to opening and closing it manually.

What’s worse, if the sensors aren’t able to identify when something such as a car or person is beneath it, and comes down anyway, it can have disastrous consequences.

Let’s take a look at how garage door sensors work and how you can troubleshoot some of the most common problems.

How Garage Sensors Work

In the most basic sense, garage door openers work by pressing a button that sends out a signal to a motorized trolley which in turn moves the garage door up or down.

One key difference is in how those buttons are wired to the garage door. Some are wired into the home itself and connected to the garage door by internal systems.

Others are remote controlled and send out a signal. Many modern garage door openers employ both or allow consumers the choice of which method to use.

In the case of remote controls, the system makes use of an infrared signal. At the push of a button, this activates the garage door by engaging the track and motorized trolley, pulling your garage door upward or downward.

For this type of system to work, there obviously needs to be sensors in place, and these are usually attached to either side of the garage door.

Placement is important with these garage door opener sensors. While there is a lot of room for leeway, the remote controls still have a limited range. If they are too far from the garage door, the signal will not get there, and thus the door will not open.

Additionally, while sensors do not necessarily need to be in the direct line of sight from the remote control, they should nevertheless be at least six inches off the ground so as to avoid the ground blocking the signal.

Potential Symptoms of a Problem

That’s all well and good, but what if you experience a problem? For as convenient as a traditional garage door opener may seem, that doesn’t mean that things can’t go awry and often do. After all, many garage door openers, as indicated above, make use of an infrared signal.

All it takes is for something to interfere with that signal in any way for your garage door opener to run into problems or not function.

As is the case with so much of life, the first step in fixing a problem is being able to identify that you have one in the first place. In this case, that means knowing what the symptoms of a garage door malfunction look like.

One thing you’ll want to look out for is a blinking sensor. This can be a sign that something is wrong with the sensor, in which case you’ll want to examine it for everything from damage to low batteries.

Garage doors are meant to open and close in smooth, unbroken movements. If your garage door starts starting and stopping with sudden, jerky movements, or starts reversing course from the direction it should be heading, you obviously have a problem.

The same holds true if your garage door only opens but does not close, and vice versa.

Potential Causes of a Problem

So, what can cause such a problem?

Quite a lot, in fact.

For as convenient as garage sensors are, they can still be thrown out of alignment, become dirty or damaged, or otherwise malfunction in a variety of ways.

Take the first of those, for example. While a direct line of sight may not be necessary for the door to open and close, garage door sensors still need to be in alignment with one another for the signal to be properly transmitted.

If the sensors are wildly out of alignment – such as one being at the very top of your property and the other being on the bottom, or being around a bend with its line of transmission blocked – it can cause your door opener not to function properly.

In addition, like anything else, sensors can become dirty. This is especially true in areas with heavy wind, where dust storms or soil and debris can become caked onto the sensors, covering them up.

There is also always the possibility of your sensor becoming damaged. This can happen any number of ways:

  • Cars and vehicles rubbing up against it can damage the internal workings
  • These may also start to break down as the result of usage over time
  • In addition, the vibrations from the garage door opening and closing can also sometimes jolt components loose
  • Direct sunlight can also damage the sensors over time

How to Fix Some Common Problems

Whatever the cause of your garage door problems, the biggest questions on your mind are probably how to fix it, how fast you can do so, and if you’ll need to call professionals to help.

To answer the last question first, while there are certainly cases where calling professionals may be necessary, especially if the following methods don’t work, there are often many ways to try and troubleshoot garage door problems yourself.

Naturally, this will depend in part on what your particular problem is. If it’s something as simple as sensors being filthy and not receiving signals as a result, you hardly need experts to help you with that. A bucket of water, some paper towels, and a little elbow grease should suffice.

If your sensors have become misaligned, you’ll need to take further action. This is one of those causes that should trigger flashing lights on the unit, indicating a malfunction.

First, make sure that the power to the sensors is turned off. Once you have done that, set to work realigning the sensors so that they are in clear range of one another.

If the unit is in direct sunlight, move it to a spot that is in the shade where the sun cannot “blind” the sensors.

If you have done all of this and still seem to be struggling with the units, or believe there to be a pinched wire or other internal malfunction, however, you will likely need to call in the pros. Trying to open these sensors yourself will likely void any warranty you have.

Thankfully, however, with the right insight into how garage door sensors work, you should be able to manage most problems with them opening and closing yourself.

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