Your garage door sensors are an integral mechanism of your automatic garage door system, and the most common type of garage door sensor is called a photoelectric safety sensor. 

These make sure your garage door stops opening and closing if it senses something is in the way, preventing accidents caused by automatic garage doors. These sensors have been required by law to be part of automatic garage door kits since 1993.

Before the popularity of photoelectric safety sensors, automatic garage door sensors were mechanical. Instead of the infrared beam that detected if anything was in the way, the mechanical sensors made the garage door move in reverse once it came in contact with an object.

While the older model may have been easier to troubleshoot, the photoelectric safety sensor is a much safer option! Let’s make sure you know how to keep your modern garage door sensor in tip-top shape.

Why Your Automatic Garage Door Won’t Close

When your garage door opens but doesn’t close, stops and reverses for no reason, or has a flashing light on the wall panel, something isn’t working quite right. It may be the overhead component of your garage door opener or the sensor itself.

Common reasons why your garage door won’t close include:

But one of the most common reasons for garage doors not closing is malfunctioning garage door sensors. 

There can be various reasons why your garage door sensors stop working such as the components are damaged, things are misaligned, or the sensor is dirty.

Here are several troubleshooting tips to get your garage door sensors up and running in no time.

1. Check if the Garage Door Sensors Are Aligned

One way to tell if your garage door sensors are correctly working is to check the sensors’ lights. One light should be green, which means it’s sending a beam of light, and the other should be red, which means it receives the light. 

If you see the red light blinking, it means your sensors are misaligned. It’s surprisingly easy to knock the sensors out of alignment, especially if there is a lot of activity in your garage. If your space doubles as a work or storage area, the chances of misalignment are even higher! 

Move each light slightly to realign them. Once the red light stops blinking, it means your sensors are where they are supposed to be.

If this problem only seems to occur at a specific time of the day, it may be the sun interfering with the light beam emitted from your sensor and making it malfunction. 

If this is the case, shield the sensors from the sun’s rays with a piece of cardboard. Make sure, however, the cardboard doesn’t block the light beam from the other sensor.

2. Check if the Garage Door Sensors Are Dirty

Since your garage door sensors are just a few inches off the ground, they can easily accumulate dirt — especially if your garage door is opened frequently or you live near a busy street. 

If you live in an area that’s usually very humid or you have sprinklers near your garage door, water can enter the sensors and block the signal. Dust and moisture can obstruct your sensors from emitting or receiving the light beam. 

When this happens, clean the sensors with a soft, lint-free, dry cloth. If that doesn’t fix it, unscrew the metal holders and wipe them dry. (If you do find moisture, It is a good idea to move your sprinklers away from your garage door, so the sensors don’t continue to get wet.)

To prevent any disruption from your sensors working because it’s dirty, make it a habit of cleaning the sensor lenses at least once a year.

3. Check the Garage Door Sensors’ Wiring

Sometimes your garage door sensor will malfunction due to wire damage caused by wear and tear from regular use, pests, or the elements. When this happens, on most models, your sensor’s light will flash orange instead of red.

Inspect the wires that connect the sensors to the terminal on the opener’s back. Check that the cables are intact and for any wires that are twisted or broken. 

Untangle any tangled wires that you find, and examine the wires to ensure they are correctly connected to the terminal. The white wires should be connected to the white terminal, and the black and white wires are connected to the gray terminal.

Inspect the wires for any chew marks or signs of tampering. Also, look for water damage. Water can short your sensors and cause them to malfunction. 

If the wires are damaged, you may need to replace them. Unless you are a skilled electrician, we recommend you hire someone to replace the wires for you. Otherwise, you risk getting electrocuted! (Plus, you can actually make the problem worse and significantly damage the sensors.) 

A professional can also check the rest of the automatic garage door system for other parts that may need repair.

Damaged wires may cause your automatic garage door system to work inconsistently or incorrectly. For your safety, disconnect your garage door from the opener to avoid damage to your property and prevent any injuries. 

You can reconnect your garage door to the opener once the wires have been replaced and the sensors are working correctly.

4. Check the Power Supply

If one or both lights on your garage door sensors aren’t lighting up, there may be an issue with your power supply. Investigate if there is a power outage in the area, if your circuit breaker blew a fuse, or simply if the garage door system isn’t plugged in. 

While you are checking on the issue, you can disconnect your garage door from the opener. This will allow you to manually close and open the door until it is up and running again.

If there is a power outage in the area, your garage door opener and sensors should be operational once the power comes back. If you see your neighbors have power, check to make sure you haven’t blown a fuse. 

If the problem is your circuit breaker, unplug the garage door opener, flip the switch in your circuit breaker, then plug the garage door opener back.

How to Bypass Garage Door Sensors

While you are waiting for someone to fix your garage door, you should bypass your sensors so you can still use your garage door.

Ideally, you should bypass your garage door sensors when the door is closed. If it is open and the door spring is malfunctioning, the door might fall closed on you when you switch to manual mode.

However, it is possible that your door is open and fails to close when your sensors malfunction. When this happens, prop the door open with a piece of wood or other strong objects, so it doesn’t come crashing down when you disable the sensors. 

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Place the wood or object on either side of the garage door. Ensure they’re tightly squeezed into the gap between the door and floor, so they don’t move when you disengage the sensors. 

Find the manual release cord, which is usually red and near the garage door opener motor. Once you pull on the cord, you can now manually open and close your garage door. 

Have a helper hold the garage door in position while you take out the wood that is propping up the door, then lower the door slowly. To open the door, pull down on the manual release cord.

Remember: Disabling the sensors means your garage door can close even when something or someone is under it, causing damage, injury, and even death. Call a professional and have them fix your garage door sensors as soon as possible.

Garage door sensors can last you for years if you keep them well-maintained by cleaning them of dust and debris and tightening the screws. If you have been having constant issues with your garage door sensors, it may be time to replace them. 

How to Replace Garage Door Sensors

Replacing isn’t too difficult and should only take about 15 to 20 minutes to do. To replace your garage door sensors, you will need the following tools:

  • Step ladder
  • Pliers
  • Work gloves
  • Wire cutters
  • Safety glasses
  • Blue wire nuts 

Using your step ladder, find the garage door opener’s power cord and unplug it. Then, unscrew the wing nuts from your sensors and remove the sensors from the brackets.

Next, cut the wire attached to the sensor about an inch in length. You will use this wire to connect the new sensor, so make sure you leave enough slack. Do the same with the other sensor.

Then you will connect the black and white control wire from the new sensor to the old black and white wire using the blue wire nut. Repeat with the other sensor.

Once those are connected, move on to the white control wire. Connect the new sensor to the old white wire using another blue wire nut. Do the same on the other side.

After all is connected, you can plug the garage door opener back in and line up the new sensors. They are good when both red and green lights glow steadily.

Test the sensors by placing an object in between the two to block the beam. Try to close the garage door with the remote. The door should not close, and the lights on the motor should blink.

Nothing Helped, What Should I Do?

Suppose you’ve tried all the troubleshooting tips we’ve mentioned above, and you’re still having issues with your garage door sensors. In that case, it may be time to call a professional to troubleshoot for you.

Title Image by Jud McCranie

Editorial Contributors
Matt Greenfield

Matt Greenfield

Matt Greenfield is an experienced writer specializing in home improvement topics. He has a passion for educating and empowering homeowners to make informed decisions about their properties. Matt's writing focuses on a range of topics, including windows, flooring, HVAC, and construction materials. With a background in construction and home renovation, Matt is well-versed in the latest trends and techniques in the industry. His articles offer practical advice and expert insights that help readers tackle their home improvement projects with confidence. Whether you're a DIY enthusiast or a seasoned professional, Matt's writing is sure to provide valuable guidance and inspiration.

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