Why Does A Motion Sensor Light Keep Turning On And Off?

Motion sensor lights are good for security as they detect when there is movement and turn on the light. When an outdoor light continuously goes on and off, it can be difficult to know why. We will explain the reasons and how to prevent your motion lights from going on and off continuously.

Why Does A Motion Sensor Light Keep Turning On And OffMotion Sensor Light Keeps Turning On And Off

Example Problem: I installed a motion sensor floodlight in my backyard facing a wall. It’s hard wired into an existing electrical fixture. The motion sensor is 6 feet away from the wall. The motion detector light keeps turning on and off. I have checked and when the light comes on and there is nothing there. There are some plants and bushes near the area. Is it possible the motion light might be triggered by the wall that is hot during the day but cools during the night, like temperature changes?

Are temperature changes turning on motion sensor?

Motion sensors lights can be sensitive to temperature changes. If it is hot during the day and cold at night, the sensor may think it sees movement because the extreme temperature is expanding the plastic housing or sensor cover. Humidity can also play a role if the light is going on and off continually. See if moisture might be built up on the sensor lens or in the sensor itself.

Why would motion sensor light turn on?

Things such as trees, plants, or bushes may be be blowing from the wind and turn on your motion sensor light. Try positioning the sensor up higher to avoid sensing the movement of plants/bushes.

Small animals such as rabbits, squirrels, or birds may be flying or walking near the motion light and set it off. Tilt the motion sensor slightly higher upwards to try to avoid the light going on when it sees small animals.

Insects flying close to the motion sensor light can also set off the motion sensor light. If an insect is large enough and approaches the sensor, the light will turn on. If you have other bright lights turned on near this area, that could be the reason attracting them as bugs tend to fly towards lighted areas at night.

Why won’t my motion sensor lights turn off?

The sensitivity of the motion sensor light could be set too high. If your motion light turns on for just the smallest things, such as flying bugs or similar, try adjusting it and turn down the sensitivity. Usually there is a slide switch or a small screw you can move to turn down the sensitivity of the motion light and adjusting this will solve your issue. Adjust the sensitivity and see if the light stops turning on and off. See image below…

Motion Sensor Light Sensitivity SwitchMotion Sensor Light Sensitivity Switch

How do you reset motion sensor lights?

You may need to reset the motion detector light if it keeps turning on and off. If the motion sensor light has its own power switch, simply turn it off for 1 minute to attempt a reset. If the motion light is hard wired into your homes electrical wiring, try turning the breaker off for one minute to attempt a full reset of the motion light.


How to Reset a Motion Sensor Light

What can cause my motion sensor light to go bad?

A very sunny environment can be hard on a motion sensor. If the sun is constantly shining on your sensor, it can degrade over time and destroy it. Sunny and hot environments such as in the southwest USA can be where this happens the most. The constant hot sun can warp the plastic housing, the sensor cover, the sensor itself, or degrade the inside wiring of the light itself. If this is the case, the motion sensor light should be removed be replaced. You can try mounting the motion sensor light in a area that gets shade or under the overhang of your home to try and avoid the sun. These plastic types of motion sensor lights can last a few years in very sunny environments but much longer in areas with less sunlight.

Why is my motion sensor light not working?

If none of the above applies to your situation then the motion sensor itself or the light bulb may be faulty.

If you have a “cheap” motion sensor light, (bought on Amazon for 7 dollars) it may be false triggering or may not be working properly or the quality you expect. If you are using the motion sensor light for security, be sure to buy a reputable unit that has good reviews and has a way to adjust sensitivity. Many people use the RING system that has the motion sensor security light and a camera built in. These types of security lights/cameras have apps for your phone that allow adjusting the sensitivity very easily.

If you need some guidance as to why your motion sensor lights are continually turning on at night, please follow the solutions above. If these solutions have not fixed your problem, please leave us a comment below with what type of motion sensor or detector light you have and someone will assist you with adjusting it accordingly.

ALLEN VETTER - DIY Repair Assistant
Allen is a Home Maintenance/Appliance Tech and the author/creator of this website. He has 33 years of experience troubleshooting and repairing all types of appliances. Contact here

Leave a Comment

Your email address will not be published. Required fields are marked *

This site uses Akismet to reduce spam. Learn how your comment data is processed.