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How To Adjust Dusk To Dawn Light Sensor?

Dusk to dawn lights are a great way to save energy for outdoor lights.

They work using a photocell that detects the ambient lighting levels – when things get too dark, they close their internal switch, which means power can flow to the light fixture, switching it on.

But what do you do if the light isn’t working properly, or it’s switching on too early or too late?

Some dusk to dawn sensors can be adjusted using dials or switches on the sensor itself or with a smartphone app. Some can be disabled so that the light constantly works if you want it to as well – again, controlled with a switch on the sensor or via an app.

Let’s take a look in a little more detail at:

  • How to setup dusk to dawn lights
  • Whether the sensor can be disabled
  • Reasons why it might be staying on all day
  • How you can test your sensor

How To Setup Dusk To Dawn Lights?

family house entrance with outdoor lights during the sunset

The setup process for dusk to dawn lights varies depending on what you’ve bought. You’ll either buy:

  • Basic dusk to dawn lights that can’t be adjusted
  • Dusk to dawn lights with adjustable controls
  • Smart dusk to dawn lights with app controls

Setting up basic dusk to dawn lights is as simple as wiring them into your electrical circuit and ensuring the photocell isn’t covered by a permanent shadow.

Once wired into the circuit, it will work immediately. When it’s light, the sensor will be trigged, which will keep the internal switch open, preventing the current from activating the light bulb.

When the ambient light drops to dusk levels, the photocell will detect this and close the switch, activating the light.

Some photocells will have adjustable controls (Amazon).

They will either take the form of toggles/switches on the sensor or dials.

Sometimes these dials are flush with the sensor and are designed to be adjusted using a flat-head screwdriver inserted into the slot in the middle.

These dials usually let you adjust the lux level – the amount of light needed for the sensor to activate and turn off the light it is attached to.

The best thing to do is install the light and check how it works with the default settings.

If you feel the light is coming on too early or too late, make a slight adjustment and test it again.

The final type of dusk to dawn lights are the easiest to set up because once installed, you can play with the settings to your heart’s content without climbing a ladder or removing the light from its position.

When setting it up, you’ll just need to wire up the light, so it’s powered on and then download the relevant app to your smartphone or tablet.

From there, you’ll need to create an account if you don’t have one, and then there’ll be an option to pair it with your light.

Once that’s done you should be able to control the lux sensitivity levels as much as you need to.

Can I Disable The Dusk To Dawn Sensor?

lighted family house at night with garden and woods around

Some dusk to dawn sensors will have an on/off switch that acts as an override.

This will be located on the unit itself, or if you have a smart sensor, it’ll be in the app.

Leave this switch in the on position, and the dusk to dawn sensor will work as it should, switching off any attached lights when the sunlight is bright enough.

Flick the switch into the off position, and you’re disabling the sensor, not the lights.

So if the power source is constant, the light will always be on when the sensor is switched off.

If your dusk to dawn sensor doesn’t have an on/off switch, then you could install a switch on the circuit itself, but that switch will essentially be controlling the sensor, not the light.

So, if you have your own switch in the on position, the dawn to dusk sensor will work correctly, turning the light on or off depending on the ambient lux levels.

If your light switch on the circuit is off, then the sensor (and lights) just won’t work at all.

Unfortunately, because the dusk to dawn sensor is a switch itself, there’s no way to wire an additional switch in so that the light is always on unless you remove the dusk to dawn sensor or can disable it.

Why Does My Dusk To Dawn Sensor Stay On All Day?

lighted garden lantern in daylight in front yard full of flowers in blossom

The whole point of a dusk to dawn sensor is ensuring that your light only comes on when you need it.

You could easily just have the light constantly switched on. You may not even notice during the daytime since the sunlight will be as bright or brighter, but it’s a waste of energy.

So, when you’ve installed the dusk to dawn sensor and your light is still staying on all of the time, then it’s pretty frustrating.

It means one of three things.

Either the sensitivity has been set too high, the sensor has a fault, or it’s not been appropriately positioned.

Sensitivity Problems

If your dusk to dawn sensor has the option to adjust the sensitivity, that’s the first thing you should check.

If the light is always on, you might just have set it to be triggered by only the brightest sunlight.

So even though the ambient brightness is pretty good, the sensor thinks that it’s dusk and so is constantly leaving the circuit closed, which means that your light remains on.

Try tweaking the sensitivity settings to see if this helps.


lighted front entrance of a family house in the evening

Similarly, it could be that the sensor for your light just isn’t in the right position, and something could be shading it to make it think that there isn’t enough ambient light.

If anything is casting a strong shadow on your sensor, or it’s installed somewhere where the light isn’t very strong, you may need to relocate it.

Look for alternative locations that don’t require a huge change to the installation but would be exposed to more ambient light.

Sensor Fault

In case you’ve checked the sensitivity and the positioning of your sensor, and everything seems normal, but your light refuses to switch off, then it seems likely that you have a faulty sensor.

If the photocell is damaged – which could happen if it has cracked and been exposed to the elements, or it may just have worn out over time – then you’ll need to replace it.

Related: Do Motion Sensor Lights Use Cameras To Detect Motion?

How To Test Dusk To Dawn Sensor?

Electrical measurements with multimeter tester

You could just test your dusk to dawn sensor manually by covering up the sensor and seeing if it switches the light on or not.

But there’s a slightly more organized way, which will tell you if the problem is with the sensor or the circuit.

For this you’ll need a multimeter (Amazon).

Switch on the multimeter and check that it’s on the resistance setting, and then connect the red and black connectors of the multimeter to the input and output wires on the photocell.

Then start testing it with various ambient lighting levels. Again, you should see the resistance changing.

If it does, then the photocell is working correctly – which means any problem you’re having is more likely to be with the light fixture.

If the resistance levels are constant, then the photocell isn’t reacting and needs replacing.

Also read: Do LED Lights Need A Special Photocell?

Final Words

Adjusting the dusk to dawn sensor is usually straightforward, providing you have one that either has controls on the sensor or works with an app.

If you don’t, and your current light isn’t behaving the way you want it to, you might need to replace it with a different one.

Generally, though, they’re really simple devices that work well. So you might be pleased with a basic one that doesn’t need adjusting.

It will still ensure your outdoor space is lit when it’s dark, without having the light on all day.

Do you have outdoor lights on a dusk to dawn sensor?

Are you happy with the standard settings, or do you have an adjustable one that you’ve had to mess around with?