garage doors sensors have batteries

If your garage sensor isn’t working as it should, all your belongings inside aren’t safe, including cars, garden tools, and working tools. Testing the sensor now and then ensures that you instantly know when there’s something wrong, and you can work on fixing it before unfortunate incidents occur.

If you don’t know how to test garage door sensors, we’ll show you how to do it, and we’ll tell you what to do afterward.

Sensor Blinking-red

How to Test Garage Door Sensors in 4 Easy Steps

Testing the garage door sensor is easy and quick. It’ll take you less than an hour to ensure it’s working correctly and keeping your belongings protected. Here’s how to do it in four easy steps.

Step 1: Use Cardboard Boxes

To test the garage door sensor, we’ll use cardboard boxes. The first thing you should do is determine the height of the sensor. When choosing the cardboard boxes, make sure they’re higher than the sensors’ height, so they’ll detect them.

Next, grab a box and put it in the garage doorway, placing it in front of the sensors. Press the button that closes the garage door, and watch it descend. If it gets close to the box, then starts opening again, returning to its original place, your sensors are working.

On the other hand, if the door keeps going down, crushing the box in the process, that means there’s something wrong with your sensor.

Step 2: Adjust the Sensor Alignment

The most common problem in garage door sensors is the alignment, so that’s the first thing you should check when the sensors aren’t working.

To do so, take a look at both sensors. You’ll find an LED light on the exterior of each one. If one of the lights is blinking, that’s a confirmation that the sensors aren’t aligned. To fix the issue, tighten the screw that’s attaching the sensor to the bracket. 

If it’s already tight enough, the bracket likely needs to be bent back into position. After you do either step, the LED should stop blinking, and your sensors should start working.

Step 3: Test the Sensors Again

After you’re done aligning the sensors, open the garage door and throw away the box that you have crushed before. Grab a new box and put it in the same place, then press the button that closes the door.

If the alignment is the only problem, the door should come close to the box, then return back up to open. If it continues to come down, closing in on the box and crushing it again, the alignment may not be the only issue.

In this case, it’s time to check the lenses to see if they’re dirty.

Step 4: Clean the Lenses and Test Again

If you’re living somewhere with a lot of wind, pollution, or dust, there’s a high chance your lenses are too dirty to work properly. The dust build-up may be blocking the sensor, causing it to stop functioning.

To fix that, grab a soft, clean cloth and rub the lenses clean with it. Make sure to get any dirt and debris off the eyes and look around for spiderwebs. They could be the reason for the malfunction.

When you finish, test the door with another cardboard box. It should go back up to its place normally. If it doesn’t, there are a few extra things you may want to check. Let’s see what they are and how to make sure they aren’t causing the sensor malfunction.

What to Do If There’s Something Wrong With the Sensors

If you adjust the alignment and clean the lenses, and the sensors are still not working; there are a couple of troubleshooting steps to take. This way, you’ll know what’s wrong, even if you can’t fix it yourself.

Check for Anything Obstructing the Sensor Beams

Door sensors are extremely sensitive. If there’s any object obstructing their beam, even if it’s small, they won’t work. So, the first thing you should do is check if there’s an object close to the door that may be obstructing the sensors.

Look for any tool, box, or even a garden machine, like a lawnmower. You may even be parking your car too close to the doorway.

garage doors sensors

Check the Power Supply

Sometimes, a sensor malfunction may be a result of the lack of a power supply. The sensor may not be connected to the source, causing it to stop working. To check for that, take a look at the LED lights on both sensors.

If they’re both on, the power supply is okay. If one of them or the two are turned off, that means there’s a problem with the power supply.

Check the Sensors for Moisture

If you live somewhere moist, or the moisture levels in your garage are high, the sensor may have gotten wet on the inside. It may also happen if your sensor got exposed to rain or droplets from your sprinkler system.

We all know water and home appliances are enemies, and sensors aren’t an exception. Moisture can ruin anything if it sits inside long enough.

Check the insides of your sensors for any moisture. If there’s any, make sure to dry it properly and attach the sensors back again.

Check for Any Wear and Tear

Cheap garage door sensors can break apart pretty fast, and they’ll stop functioning if they endure too much wear and tear. If your sensor isn’t working, check it for any damage or signs of broken or torn wires.

That’s not necessarily for cheap or affordable sensors; we can say the same about sensors that have been in use for more than ten years. That long time can affect the functionality of any sensor, no matter how expensive it is.


Any problem with garage door sensors should be quickly fixed. Otherwise, you may find the garage door closing on your car one day. Even worse, everything inside becomes at risk of being stolen.

For your own peace of mind, do regular checks for the sensor, and carry out the troubleshooting steps to know where the problem is.

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