Day night sensor for outdoor lights: How to fix a day night sensor?

Don’t stress out if you have a day-night sensor and it isn’t functioning properly! If you follow these straightforward instructions to fix the issue, your sensor will be operational in no time at all. Keep in mind that some sensors are more difficult than others, so if you’re having trouble with the one you’re using, make sure to consult the instructions that came with it from the manufacturer. However, for the vast majority of sensors, these procedures should do the trick! Best wishes with the fixing!

What is a day-night sensor and what does it do?

Day-night sensor
Day-night sensor

Day-night sensors are also referred to as photocells, and they have the capability of turning lights on automatically when the sensor detects a particular level of darkness.

Due to the fact that they switch themselves on if the room temperature changes, they are an exceptional safety device. When it becomes dark outside, your day-night light sensor will turn on your vital lights for you, so you won’t have to worry about forgetting to do so.

Day and night sensors are an excellent approach to enhance the safety of your house and come with a variety of benefits:

Create the appearance that you are at home even when you are not there or when you are on vacation.
When returning late at night, be sure the conditions are safe.

During the busy evenings, when you need to switch the lights on, it will be one less thing for you to do. It will also help you save money on electricity by preventing you from leaving the lights on when they are not necessary.
Day-night light sensors are available in a wide range of sizes and amp ratings to accommodate a wide variety of applications.

For instance, if you want to connect your exterior lighting to a powerful day-night sensor, you might need to because you will probably require it to illuminate a broad area with a variety of lights that each have its own amperage.

How to fix a day-night sensor?

This Instructable will show how to fix an automatic daylight sensor for lighting, how it works, and how to wire it up.

  • Step 1: Find the mistake.

Find the mistake
Find the mistake

In this case, it was easy to figure out what was wrong with the appliance because the problem could be seen. However, sometimes you can’t see the problem with your eyes and need to use a tester. As you can see in the picture, both the main capacitor and resistor were blown (probably by a surge of voltage).

  • Step 2: Take the blown parts off the solder.

Take the blown parts off the solder.
Take the blown parts off the solder.

Just get a soldering iron and use it to take the capacitor and resistor apart. It’s easy if you put a bit of solder on the end of the tip, heat it, and then use pliers or tweezers to pull out the parts. The capacitor for the mains was broken, and the resistor was in two pieces.

  • Step 3: Replacement Parts

Replacement Parts
Replacement Parts

The parts for the new board came from another old one. The resistor was 150ohms and the mains capacitor was a different color, but it did the same job. Put the parts back where they belong and, if necessary, bend the legs of the capacitor. Because the legs of the capacitor were short, the resistor had to be moved to the other side.

  • Step 4: The theory behind the capacitor power supply

The theory behind the capacitor power supply
The theory behind the capacitor power supply

A capacitive power supply is a type of power supply that lowers the mains voltage by using the capacitive reactance of a capacitor. There are two major problems: First, this type of power supply is usually only used for low-power applications because the capacitor needs to be able to handle a high voltage and a high capacitance for a given output current. (In general, a capacitor of a certain size or price can have either a high voltage rating or a high capacitance, but not both.) The second problem is that there is no electrical isolation. Because of this, the circuit must be encased and separated so that users don’t come into direct (galvanic) contact with it.

We can get a current of 20 mA by replacing the example in the diagram with a capacitor with a value of 330 nF. This way, you can power up to 48 white LEDs (for example, 3.1 V/20 mA/20000 mcd) if they are connected in series. But the picture shows an open lamp with 48 LED diodes at a party. At 50 Hz, the reactance of the 1.2 F capacitor is 2.653 kohm. Ohm’s law says that the current can only be as high as 240v/2653ohm = 90 mA if the voltage and frequency stay the same.

  • Step 5: How Does It Work?

How Does It Work?
How Does It Work?

A light-dependent resistor (LDR) is the main part that makes it work. This resistor is more resistant when it’s dark and less resistant when it’s light. Some electronics turn on a relay when it’s dark (more resistance) and turn it off when it’s light (less resistance) (less resistance).

Don’t forget that this is high voltage and could kill you! So be aware of the risk. Wiring it is easy; just follow the diagram and you should be fine. Put the sensor together and give it a test, and you’re done.

Dusk to dawn light sensor not working

Dusk to dawn light sensor not working
Dusk to dawn light sensor not working

The mechanism behind dusk-to-dawn lights is deceptively straightforward: they come on at nightfall and turn themselves off in the morning.

If the lights do not switch on and off as they are supposed to, then we are left wondering what the specific problem was that caused it.

If you’ve ever found yourself wondering, “Why isn’t my outdoor dusk-to-dawn light sensor working?” this article is for you. alternatively, “why isn’t the dawn-to-dusk portion of my light sensor working?” you’re not alone.

Incorrectly functioning sensors are really one of the most typical causes of issues with dusk to dawn lights.

But there’s no need to worry because I’m here to assist you.

I have included a list of all the potential explanations for why your light sensors are not functioning, as well as instructions on how to get them back up and running.

Here we go!

Why Your Dusk-to-Dawn Light Sensor Isn’t Working and What You Can Do About It

The sensors on dusk to dawn lights are susceptible to unexpected failure, just like the sensors on most other sensor-powered pieces of equipment.

Here are some possible reasons why:

  • Sensors That Are Blocked

Sensors That Are Blocked
Sensors That Are Blocked

If the sensors are hampered in any way, whether by dirt, trash, or even shadows cast by trees, buildings, or other objects, they will not function properly.

After all, the performance of sensors is determined by the surrounding environmental stimuli.

As a result, lights that stay on from dusk until dawn should always be positioned in an area that has a lot of natural light.

  • Bad Bulbs

Bad Bulbs
Bad Bulbs

If the sensors are attached to broken bulbs, it stands to reason that they won’t function properly.

There are a number of factors that can contribute to the “burning out” or “death” of light bulbs, including high power, recessed illumination, poor contacts, and weak connections.

It’s also possible that they had just reached the end of their shelf life. For example, incandescent light bulbs can only be used for around 1,000 hours before they completely fail.

The only way to fix burned-out bulbs is to get new ones and put them in their place. Right?

  • A Photocell That Is Damaged

A Photocell That Is Damaged
A Photocell That Is Damaged

If the lamp continues to behave in an unusual manner even after you have removed all barriers from its path and replaced its bulbs, the problem most likely lies in the photocell.

The thing is as follows:

Photocell sensors typically have a life expectancy of more than ten years.

However, they can develop problems from time to time, which is especially likely if the wiring that they are attached to is unstable.

When this happens, replacing a faulty photocell with a new one is the most effective way to remedy the problem.

Because photocell sensors are quite inexpensive and frequently include lengthy warranties, purchasing them might be considered a smart investment in the long run.

  • Loose Wiring

Loose Wiring
Loose Wiring

If you have tried everything possible to get your dusk-to-dawn light to turn on, but it still isn’t, the problem may not be malfunctioning sensors but rather a loose wiring.

A sloppy wiring job may make any light behave strangely, from fluorescent lights that flicker on and off to lights that receive no electricity at all.

However, in this case, it is of far more concern:

Due to the fact that they generate aberrant arcs around the point of connection, unkempt wires can cause a significant amount of damage to dusk-to-dawn light sensors.

Because of this, they should be inspected and maintained on a consistent basis at all times, and this is especially important if you live in a location that is more prone to rain, floods, and other natural disasters.

  • Voltage That Is Continually Changing

Voltage That Is Continually Changing
Voltage That Is Continually Changing

The flickering on and off of your dusk to dawn lights, as well as frequent and unexplained extinguishing of the lights, could be an indication that the voltage in the area is not stable enough.

Although it is not unusual for there to be some variations in voltage, the total voltage in your home should always read between 115 and 125 volts.

Your dusk-to-dawn lights won’t function correctly if the average reading is below 115 or above 125, respectively, so make sure to keep an eye on it.

The voltage that is unstable is frequently the result of connections that are either loose or damaged.

In the interest of your well-being, you should consult an electrician about finding the most effective answer to this problem.

  • System Issues

System Issues
System Issues

It is possible that a problem with the system or an override is preventing your dusk-to-dawn light sensor from functioning properly.

After a power outage or a slight fault with the light’s system, such as poor wiring, it is usual for there to be difficult with the system.

Thankfully, problems with the system that controls the lights that turn on in dark and turn out in the morning are simple to resolve.
Simply switching the lights on and off will restore their previous settings. That sums it up nicely.

How to Fix a Faulty Dusk-to-Dawn Light Sensor

Depending on the root cause of the problem, there are multiple solutions available for repairing malfunctioning dusk-to-dawn light sensors.

These strategies can be of assistance to you!

  • Reset the light that turns on from dusk to dawn

It is possible that the problems you are having with the sensor can be fixed by resetting the dusk to dawn light, as is the case with most electrical devices.

Because the mechanisms inside dusk to dawn lights aren’t extremely intricate, resetting the lamp is as easy as turning off the wall switch, waiting approximately six seconds, and then turning it back on again.

  • Clear the Path of Any Obstacles

As was just mentioned, it is possible that the photocell sensors are not functioning properly because they are obscured by dirt, dust, debris, or other obstructions that stop light from accessing the cells.

In the event that this is the case, you will need to unscrew the bulb and clean the dust that is blocking the sensors.

Take care to avoid causing any accidental harm to the photocells by doing this.

If the sensors are still not functioning as they should, you should relocate the lamp to an area where there are no obstructions to the light.

Place it in an area that is free from shadows, large buildings, trees, and any other obstacles that could prevent natural light from entering.

I am aware that there are instances when this is challenging!

Be sure that the lamp is not facing a wall or that it is not positioned inside of a fixture that prevents it from receiving sunlight.

  • Replace the Sensor of the Photocell.

If you have removed any impediments from the area around your dusk-to-dawn sensor and it is still not functioning properly, the problem most likely lies with the photocell itself.

When light strikes the surface of a working photocell, the reading should change from “0” to “1020,” and vice versa when no light is present.

If the reading from the photocell is incorrect, the problem is most likely caused by a short circuit in the wires.

If this is the case, you will need the assistance of a trained professional to replace the sensor in the lamp with a fresh new one.

  • Check to See That You Are Employing the Appropriate Light Bulb and Ballast

It’s possible that the problem is that you’re using a bulb or ballast that isn’t compatible with your sensors.

Check the three-letter ANSI code that is printed on the bulb to ensure that it is compatible with the ballast.

If it does not, you should replace it with a different brand that is compatible.

  • Make Repairs to Wiring That Is Loose or Defective

Wiring that is loose or damaged can be the source of a wide variety of electrical problems, including defective sensors.

If your light that turns on automatically at nightfall and turns out automatically at dawn isn’t functioning as it should, you should inspect the condition of your wiring.

Calling a professional electrician should always come first before attempting to fix the wiring on your own.

It is not a do-it-yourself effort to fix broken wires, particularly if you do not have prior background information on the inner workings of the device.

A poor wiring setup has the potential to cause severe shock dangers as well as electrical fires if it is used improperly.

Do not put yourself in danger by engaging in possibly lethal activities in order to save a few dollars.



Day-night sensors are an essential component of the home security system you have installed in your property. You can assist in keeping your family as well as your property safe and secure if you are familiar with how to repair a day-night sensor and how to solve typical issues. Make sure to get in touch with our staff for help if you have any concerns or questions regarding the installation or maintenance of a day-night sensor.

Recent Posts