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Dusk to Dawn Light Sensor Not Working? 7 Ways to Fix This Handy Auto-Feature

Dusk to dawn lights have a simple yet ingenious mechanic: they turn on at sunset and turn off at sunrise. 

So if the lights don’t turn on and off like they’re meant to, we’re left wondering what exactly went wrong.

If you’ve ever asked the question, “why is my outdoor dusk to dawn light sensor not working?” or, “why is the dawn to dusk part of my light sensor not working?” you’re not alone. 

Faulty sensors are actually one of the most common problems of dusk to dawn lights. 

Fret not, though; I’m here to help.

In this article, I’ve listed all the possible reasons why your light sensors aren’t working, and how to get them back up and running. 

Here we go!

Reasons Why Your Dusk to Dawn Light Sensor Isn’t Working

Like most sensor-powered equipment, the sensors on dusk to dawn lights may suddenly stop working as they should. 

Here are some possible reasons why: 

1. Obstructed Sensors

If the sensors are obstructed by dirt, debris, or even shadows from trees, buildings, etc., they won’t work as they should. 

Sensors rely on environmental cues to work, after all. 

Therefore, dusk to dawn lights should always be placed in an area with plenty of natural light. 

2. Bad Bulbs

Change the Bulbs

Naturally, the sensors won’t work if they’re connected to bad bulbs. 

Light bulbs burn out or “die” for several reasons, including high voltage, recessed lighting, bad contacts, and loose connections. 

They might have also simply reached their expiration date. Incandescent light bulbs, for example, burn out after about 1,000 hours of use. 

The only solution to bad bulbs is to replace them with new ones. Right?

3. Damaged Photocell 

If the lamp continues to exhibit odd behavior even after you’ve replaced the bulbs and removed obstructions, you most likely have a bad photocell

Here’s the thing: 

Photocell sensors have a lifespan of upwards of 10 years. 

They do go bad from time to time, though, especially if they aren’t connected to stable wiring. 

In such cases, the best way to fix a bad photocell is to simply replace it. 

Photocell sensors aren’t expensive and often come with long warranties, so they’re excellent investments in the long run. 

4. Loose Wiring 


If your dusk to dawn light isn’t turning on despite your best efforts, it might be due to loose wiring rather than faulty sensors. 

Loose wiring can cause any light to misbehave, from fluorescent lights going on and off to no power at all.

But here it’s extra concerning:

Unkempt wires can cause a lot of damage to dusk to dawn light sensors as they cause abnormal arcs around the point of connection. 

For this reason, they should always be checked and maintained regularly, especially if your area is more prone to rain, floods, and other natural calamities.

5. Fluctuating Voltage

If your dusk to dawn lights keep flickering on and off, or if the lights frequently burn out for no apparent reason, this could be a result of fluctuating voltage. 

Slight fluctuations in voltage are normal, but your home’s overall voltage should always read between 115 and 125 volts. 

If your average reading is under or over 115 and 125 respectively, your dusk to dawn lights won’t work properly. 

Fluctuating voltage is often caused by corroded or loose connections. 

For your safety, call an electrician to help you with the best solution to this issue.

6. System Issues

electrician issues

Your dusk to dawn light sensor may not be working because of system issues or overrides. 

System issues commonly occur after power outages or minor problems in the light’s system, like incorrect wiring. 

Thankfully, system issues concerning dusk to dawn lights are the easiest to fix. 

Simply reset the lights by turning them on and off. That’s it. 

How to Fix a Faulty Dusk to Dawn Light Sensor

Fix a Faulty Dusk to Dawn Light Sensor

There are several ways to fix faulty dusk to dawn light sensors, depending on why it’s not working. 

These methods can help you out! 

1. Reset the Dusk to Dawn Light 

As with most electrical devices, resetting your dusk to dawn light may fix the issues you’re facing with the sensor. 

Dusk to dawn lights don’t have overly complicated mechanics, so resetting the lamp is simply a case of turning the wall switch off for about six seconds and turning it back on.

2. Remove Obstructions

As discussed above, photocell sensors may not be working because they’re covered in dust, dirt, debris, or other fixtures preventing light from entering the cells.

If this is the case, open the bulb and wipe away the dirt obstructing the sensors. 

Do this gently so you don’t accidentally damage the photocells.

If the sensors still aren’t working as they should, move the lamp to a location where light isn’t obstructed. 

Position it away from shadows, tall buildings, trees, and other barriers that may block natural light. 

I know, this can be hard sometimes!

Make sure the lamp isn’t facing a wall or placed inside a fixture without access to sunlight.

3. Replace the Photocell Sensor 

If your dusk to dawn sensor still isn’t working after removing the surrounding obstructions, you’re probably dealing with a faulty photocell. 

A functional photocell should read “1020” when light hits its surface and “0” when light doesn’t. 

If the photocell doesn’t read correctly, the wires have probably short-circuited. 

Should this be the case, install a brand new sensor into the lamp with the help of a professional.

4. Ensure You’re Using the Right Bulb and Ballast 

Your sensors might not be working because you’re using an incompatible bulb or ballast. 

Check the bulb’s three-letter ANSI code and make sure it correlates with the ballast. 

If it doesn’t, replace it with a compatible brand.

5. Fix Loose or Faulty Wiring

Loose or damaged wiring can cause a myriad of electrical issues, including faulty sensors. 

So, it’s always worth checking the status of your wiring if your dusk to dawn light isn’t working as it should. 

Before you go fixing the wires yourself, though, always call a professional first. 

Fixing broken wires isn’t a DIY project, especially if you don’t have prior background knowledge on its inner workings.  

In the wrong hands, faulty wiring can create serious shock hazards and electrical fires. 

Don’t risk potentially deadly accidents just to save a couple of bucks. 

How to Increase the Life of Your Dusk to Dawn Lights 

Increase the Life light sensors

Dusk to dawn lights have an estimated lifespan of 30,000 to 50,000 hours if taken care of properly. 

Follow these steps to ensure the longevity of your dusk to dawn light fixtures: 

  • Place the lamp in an area with consistent lighting
  • Use LED lights that operate at low current 
  • Get your wiring checked by a professional once or twice a year
  • Operate the lamp with a reliable power supply 
  • Equip your automatic lamp with high-quality drivers and ceramic capacitors

To help with some of the above, here’s a short video when it comes to installing these lights in the best way:

Frequently Asked Questions

Does dusk to dawn light need a switch?

Dusk to dawn lighting can be installed without a switch, but it’s highly recommended to do so because light switches allow you to manually turn the lights on and off at any point of the day.

Can you convert a standard light to a dusk to dawn light?

Yes, you can! Simply replace the existing bulb with a bulb equipped with a photosensitive light sensor

Do dusk to dawn lights use a lot of electricity?

Absolutely not. In fact, its low energy cost is one of its selling points! 

Dusk to dawn lights use fewer watts than standard lighting. 

Plus, it only turns on when night falls, reducing electric wastage.


As you can see, fixing faulty dusk to dawn light sensors is fairly straightforward. 

So, whenever you’re facing with your dusk to dawn light sensor not working, simply follow the methods above and it’ll be back up and running in no time. 

Good luck!

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