How Do I Know If My Garage Door Sensor is Bad?

How Do I Know If My Garage Door Sensor is Bad?

Garage door sensors are very important to a garage door and they should not be taken for granted at any time. Overlooking the garage door sensors is as good as not taking good care of your room because anything that affects the garage door sensor would automatically affect you and end you up in parking your cars outside or not able to move them out because of the garage door would not work.

Garage door sensors are connected to automatic garage doors and can go a long way in controlling any form of activity that goes on in the garage, the entry and exit of both automobiles and human beings from the garage, the safety of lives, properties, and pets in the garage and other important things.

A bad garage door sensor means that nothing is going to work inside the garage. When such happens the owner of the garage would turn stranded either inside the garage or become frustrated outside the garage.

Therefore, the question is, how do I know my garage door sensor is bad? The best way to know if your garage door sensor is bad is if the garage door fails to open and close or follow the command of the sensor, if there is wear and tear on the wires, wetness on the sensor, dust or dirt on the sensor, obstructions on the sensor partway. etc. These are the indicators that the garage door sensor is bad.

Sensors on Garage Door: An Overview

Garage door sensors are device control that regulates an automatic garage. They are mainly manufactured to help enable the garage door to open and close anytime it is needed, and they are also there for safety reasons in the garage. The sensor helps to avoid accident occurrences seen in the garage.

One of the most important parts of a garage door sensor is the photo-eye. Every sensor is manufactured to have two photo eyes inserted on the opposite sides of the garage door opening. The photo-eye ensures that the part of the garage door is not obstructed by anything when the garage door is working. The garage door stops functioning once the photo eyes are unable to contact one another.

The garage door sensors help to detect any form of obstruction on the garage doorway. They help the garage door to function optimally and make it safer for both the users and any kind of automobile that moves in and out of the garage. Without the sensors, the garage door cannot work, this is to say that garage door sensors are the life wire of any garage door and must be handled with care.

Functions of a Garage Door Sensor

Here are the functions of the garage door sensor:

  • Opening and closing of the garage door.
  • Safety of life and property.
  • Gives command to the garage door.
  • Enhances the easy entry and exit of automobiles, human beings, and pets into and out of the garage.
  • Regulates and prevents unwanted visitors from gaining entrance to the garage.

How to Test Garage Door Sensor

To carry out an effective test on your garage door sensor, you will use the cardboard box test. Ensure you block the cardboard box in the line of the door sensors and try to close the garage door. If the door reverses because of the obstruction on the way of the sensor, then it means your garage door is working well. If the door closes on the box then you would have to troubleshoot and know the exact problem with the garage door sensors.

How to know If the Garage Door Sensor Bad

Here are how to know if the garage door sensor is bad:

  • When the garage door stops opening and closing in a proper way
  • Obstruction on the partway of the garage door sensor
  • Lack of adequate power supply for the sensor, if both lights on the sensors are not showing then there might be issues with the sensor
  • If the garage door sensor is dirty or wet
  • Check the wires to know if there are any wear and tear on them.

Reasons why Garage Door Sensor is Not Working

So many things constitute the reason why a garage door sensor would develop a fault and if care is not taken the garage door would stop working. Such reasons include the following:

1. Wire Damage

This is one of the most common reasons that can lead to a garage door sensor stops working. Different sensors show different lights to indicate when there is wire damage or a related issue in the sensor, if the sensor starts blinking orange light instead of the regular red light; it is an indication that there may be a wire damage issue with the sensor.

At this stage, it is required that you thoroughly take a good look at all the wires in the sensor, from the terminal to the back of the opener in the sensor. If there be issues with the wires hanging or weaved together amongst themselves, carefully unweave and check if any of them is already damaged. If you notice any damage to the wires, quickly alert your electrician to help you remedy the situation or you do that yourself if you have good electrical knowledge.

2. Power Supply in the Sensor

Once the green light in the sensor is on, it shows that there is no challenge with the sensor, and at the same time, it shows that the power supply of the sensor is functional. But peradventure both lights on the sensor are not showing, and then you should know that the sensor is having a power supply challenge and the sensor would not be able to pick any command. When this occurs, quickly check if the sensor cables are not plugged to avoid the garage door closing on itself. Most power supply fault is caused by faulty fuse either due to low power supply or a drop in the voltage.

3. Sensor Lenses

Dust and dirt can damage the sensor lens. Once you have a dusty garage or you always leave the garage open, dust and dirt would accumulate on the sensor lenses and thereby cause a problem for the garage door sensor. Excess humidity can also be another factor to cause damage on the sensor lens, that’s if you live in a wet environment. What to do at this stage is to wipe off the water on the sensor or clean the dust and dirt on it and dry it up, also open the metal holders with a screwdriver to check if the inside panel is wet or dusty.

4. Photo-eye Sensor Lights

This eye measures up to 6 inches or 15 cm above ground level. The garage door sensors have green and red lights on each of them, once anything goes wrong with the sensor one amongst the two lights would automatically go off. It means that the senor is not receiving a signal from each other or that they are not working at the same level and as such would not perform.

The remedy to this is to always ensure you protect the sensor from the rays of the sunlight by covering it with cardboard paper. And ensure you fix the cardboard properly so it would not stop the sensor from receiving commands from each other.

5. Garage Door not Closing

This is another way to decipher when the garage door sensor is not working. If the door opens well but refuses to close back, then something is wrong with the sensors. Similarly, when the garage door closes and opens immediately then there is something wrong with the sensors. The remedy to this is the cardboard box text explained earlier.

Garage Door Sensor Troubleshooting

When you notice any kind of challenge on the garage door sensor, quickly carry out the following troubleshooting process:

  • Sweep off any object on the garage floor that may be a form of obstruction and impediment on the senor part ways.
  • Quickly check the wires on the sensor by unscrewing the sensor panel.
  • Wipe off any form of dirt or dust on the sensor, even when you feel there is no dirt or dust on it. Prevention is better than cure.
  • Check the alignment and know if it is in good shape, if not then adjust it to the proper way by ensuring that they are facing each other.
  • Dry up any form of wet or water on the sensor.

If peradventure none of the troubleshooting processes worked for you, quickly check the manual and see if there are additional ways you can troubleshoot, if there is none, then you must call an electrician to come to your aid.

How to Fix a Garage Door Sensor

While trying to fix your garage door sensors, the following must be handy:

  • Clean rag
  • Small adjustable wrench
  • Stepladder
  • Small screwdriver
  • Electric pliers
  • Double-strand insulated low-voltage wire (depends on choice)

The garage door sensors can be fixed by doing the following:

  • By cleaning the sensor and adjusting the alignments
  • Unscrew the small nuts on the sensor and hold the sensors to L-brackets with an adjustable small wrench.
  • Ensure the sensors are facing each other properly,
  • Keep adjusting the sensors with your hand until the green and red light comes up on each of the sensors.
  • Ensure there is good electric voltage for the sensors to avoid the fuse blowing up at any time.
  • Unplug the power cord, remove the cover and identify if there is any issued there.

It is always better to call a licensed and professional electrician to come to check your garage door if it’s not working well. The only way you can do it yourself is if you know what you are doing.


The functions and importance of the garage door sensor to the garage cannot be overemphasized, when overlooked a lot of bad experiences would be the outcome. It is important to know when your garage door is bad and always take care of the garage sensor doors at any point to enable the sensor to serve you well while you enjoy peace and safety in your garage.