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How to tell if Garage Door Sensor is Damaged


November 19, 2025

It is vital for one to know how to tell if the garage door sensor is bad. Sensors malfunction due to a number of reasons. Below are steps to guide you through the assessment process.

1. Measure the door sensors height

Measure the height of the garage door sensors to get the required height of objects to block it. Remember that the sensors block the door from opening or closing if it senses an object near.

2. Obtain boxes

Get some boxes, preferably made of cardboard material. Measure the height of the boxes to ensure that they have a height higher than that of the door sensors. Arrange the boxes in the garage doorway, just in front of the sensors.

3. Test the sensors

Ensure that the door is open and activate the opener. You can choose to press the close button located on the wall of the garage or the remote button. If the garage door closes, it indicates that the sensors are not functioning. In this case, check the alignment of the opener or better, involve a technician. However, if the door goes back to the open position, then the sensors are working as they should.

4. Check the sensors’ LEDs

Each of the sensors mounted on the garage door has a LED light located at the outer side. Put on the electric power supply and look at each LED on both sensors. If you notice that any of the LEDs has a blinking light, it is a sign that they need to be aligned to function properly. You can simply adjust the sensors by tightening the screws supporting them. If the blinking is still on, bend the bracket to tilt it back to the right position. Contact a technician if the LEDs continue to blink.

5. Clean the lenses

The door sensors lenses are prone to dirt that blocks them from functioning properly. Check for dust particles and cobwebs that can make the sensor lenses to malfunction. Clean the lenses using a lint free soft cloth.

6. Check for objects in the surroundings

Test the door to assess if it will still crush the box you have placed in front of the sensor. If the door closes down, check for the objects that may be present near the garage door. Remove plants, garden tools, animals from the doorway. Close the door to check whether it remains open an indication that the sensors are functioning well.

7. Assess for wetness

If the sensors were exposed to direct rain water or sprinkler or pressure washer, they may fail to function. It is advisable to wait for them to dry before testing whether they are working properly.

8. Check for wire damage

Any wire damage may cause the sensors to fail. Look if the wires are broken or chewed. Excessive water from the rain or sprinkler may cause short circuit to the sensor leading to malfunction. In case of wire damage, the sensors should be replaced. If you live in Fort Mill SC You may want to seek professional garage door assistance for wire damage assessment and possible sensors replacement.

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