Why Do My Motion Sensor Lights Keep Flashing On and Off?

2016 Oct 19
Posted in: Electrical

Your motion sensor lights are supposed to give you a sense of security and peace of mind.

Instead, they’re driving you crazy because they won’t stop turning on and off, regardless of whether there’s an actual intruder setting them off or not.

If your motion sensor lights keep flashing on and off, you should try:

  • Checking whether they’re actually flashing on and off or just flickering
  • Adjusting the motion sensor positioning and settings
  • Adding “side blinders” to your sensor

Let’s take a closer look at some of the ways you can stop false alarms from your motion detector lights. 

If you’re not up for any DIY troubleshooting, just contact us and we’ll send over one of our electricians to find and correct the problem.

First off, are they flashing on and off or just “flickering”?

If the problem is that your motion sensor lights are flickering, you have a completely different problem than the one we’re addressing in this article.

Flickering lights (lights that produce unsteady, rapid changes in brightness) are usually caused by one of 3 things:

  • A bad bulb
  • Bad connection between the bulb and the light fixture
  • Problems within the circuit 

See "Why Do The Lights In My Home Keep Flickering?” for more help on this problem.

So if you have a motion sensor light that flickers when it’s on, we suggest you first try changing out the bulb. If this doesn’t fix the problem you’ll want to have an electrician check the circuit for bigger problems.

However, if the problem is that your motion sensor lights are false-triggering, continue reading below for some troubleshooting tips.

Adjust the sensor settings

Most motion sensor lights have an easily adjustable sensor. This sensor “trips” when it senses a significant change in the level of heat within its vision (that is, an intruder moving within its view).

Now, if the sensor is positioned poorly or if the settings aren’t set correctly, it may pick up heat from areas it shouldn’t (for example, movement from branches, cars in street, etc.). Use the steps below to make sure your motion lights are positioned and set according to your needs.

1. Move the sensor from “Operational” to “Test” mode. This switch is located on the bottom of the sensor and turns the light off after a few seconds, allowing you to test different settings quickly. 

2. Make sure that the sensor is directly facing the area you want it to “guard.” If you want it to pick up on movement within the driveway, make sure it’s tilted down far enough to prevent catching movement from the street but high enough so that it isn’t going off when the breeze stirs the flowers lining the driveway.

3. You can also check the bottom of your sensor for a “range” dial. This switch dictates the distance that your sensor will detect heat/movement. If it’s set to “max”, lower the range. 


4. Adjust any pet immunity sensors. Some motion detectors allow you to choose a pet immunity setting so that the detectors won’t trip when pets up to a certain weight pass by. First off, make sure that yours is on if you have pets (either yours or a neighbor’s). Secondly, most pet immunity settings allow you to choose a weight setting. Make sure yours is set to the weight that matches the animals likely to pass by the sensor’s field of vision.

5. Reset your sensor to “Operational” mode when done.

If you’ve played with all of these settings but find that your motion lights are still going off when they shouldn’t be, continue on to our next tip.

Try “side blinders”

Every motion detector light sensor has a particular angle range. Most angle ranges are anywhere from 180 degrees to 360 degrees.

But sometimes, a sensor’s angle range is too wide and is triggered by unnecessary movement, like tree branches swaying.

Try putting thin pieces of electrical tape on one or both sides of your sensors to narrow its field of vision. This can be a “trial and error” process as you experiment with various thickness of tape so be sure to put your sensor in “Test” mode first.

Motion lights still triggering false alarms? Ask an AZ electrician

If you’ve tried the above troubleshooting steps but your motion lights are still turning on and off, you might have a larger electrical problem.

Don’t worry, we’re here to help. We can inspect the system, find the cause and correct it.

Just schedule your appointment with our electricians today and we’ll send one over as soon as possible.

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