Pool Light Troubleshooting

Written by Michael Dean
April 27, 2023

troubleshooting a pool light

A good pool light makes your water seemingly glow and allows you to swim safely at night. However, when pool lights don’t work, it casts a shadow over everything!

So what do you do when your pool light doesn’t work? You don’t necessarily need to call a professional or drain the pool. There are some simple things to check first; below is my advice for pool light troubleshooting.

Main Takeaways

  • Before working with electricity, make sure you have a multimeter to ensure the electricity is off.
  • Some common pool lighting issues include: loose light fixture, leaky pool light, tripped breaker, light bulb gone out, tripped GFCI, bad breaker, and line continuity.
  • Some fixes may be as easy as tightening the screw or replacing the bulb, but other issues may require some basic electrical knowledge.

Safety First!

Before I go any further, I want to stress the importance of putting safety first for whatever project you’re doing. For swimming pools especially, because water and electricity don’t mix. So before troubleshooting, turn off the electricity to the pool in your breaker box. Then, flip the ground fault circuit interrupter (GFCI). Flipping the GFCI ensures electricity doesn’t accidentally flow through the circuits.

Finally, use an electrical test meter or multimeter (available at most hardware stores) to triple-check that the electricity is off.

Have you done that? Okay, let’s get into some common issues and how to fix them.

Loose Light Fixture

A loose lighting unit is one of the more straightforward fixes. A single screw, called a lock-screw, affixes your pool lights to your pool wall. You can find it at the very top of the face of the light fixture. If the ring fixture that holds the light into the pool wobbles when you touch it, you have to tighten the lock-screw.

How? Get yourself a Phillips screwdriver and some swim goggles. Take a dip and tighten the screw. It’s that simple.

Leaky Pool Light

If you are swimming with goggles, it’s good to check your pool lights for leakage. Engineers designed the light fixture to stay dry, and water in the housing means the bulb could blow at any moment. If you see a water line in your light, it means you have a warped or broken lens gasket, and it’s time to get to work!

The lens gasket is the rubber ring that seals the plastic housing, and chlorine and old age can cause them to warp and disintegrate. Don’t worry. It’s an easy fix that pretty much anyone can do. It’s as easy as removing the lock-screw and pulling the light out of the pool wall. You don’t need to drain the pool for this!

There should be enough cable to rest the light on the pool deck. Remove the lens frame and take out the old gasket. Replace it with a new one and reassemble the housing unit, ensuring everything is nice and dry. Then, place the unit back into the wall and refasten the lock-screw.

Tripped Breaker

If your pool lights aren’t working, one of your first visits should be to your breaker box, located in your basement on the side of your house. Electrical engineers design breakers to automatically “trip” when overloaded with electricity.

Your breaker box will have at least one breaker dedicated to your pool. Occasionally, you can overload the circuit and the circuit breaker will be tripped.

Are your pool breakers tripped? Head over to your breaker panel – they’ll be in the OFF position with a red or yellow square showing beside it. The first thing to do is unplug any extra appliances you may have on the same circuit.

Then, reset your breaker by pushing it so that it is entirely off, then moving it the other way to reset it. If the breaker automatically flips back to OFF, you may need a new breaker.

The Light Bulb Has Gone Out

If you checked the breaker and the light is still out, it may be that the bulb itself has burnt out. How many people does it take to change a pool light bulb? Just one (maybe two)! Follow the instructions above (for changing the lens gasket) and get the housing unit on your pool deck.

Remove the bulb and shake it next to your ear. If you hear something loose inside, it means the filament has burnt out, and you need to replace the bulb.

So screw in your new bulb and test it, which may get a bit tricky. Pool lights are often halogen, and even brand-new bulbs will burn out quickly outside of water. So once you screw your new bulb, check to see if it works by turning the power back on to the pool. But do it quickly! You may need a friend to look at the light while you turn on the power.

I have an entire article on how to replace a pool light bulb that you can read for more detailed instructions.

Pro-tip: putting a bit of dielectric bulb grease in the socket will make the bulb much easier to remove the next time you have to change it!

Tripped GFCI

The ground fault circuit interrupter (GFCI) is a safety mechanism designed to lower electrocution risk. You can find GFCI buttons on electrical outlets in your bathroom or kitchen, anywhere where electricity and water might mix. There is probably one in your circuit breaker box.

The GFCI reads the current traveling through a circuit and shuts it down if it detects any changes. They can be pretty sensitive and prone to “nuisance tripping,” where they shut down the current despite no danger. What causes nuisance tripping? Long circuits (more than 100 feet), fluorescent bulbs, and motors like exhaust fans.

GFCIs also need to be replaced every once in a while, so test your every month.

Bad Breaker

The following two troubleshooting techniques require what’s called a multimeter. A multimeter can detect where there might be a problem in your pool’s electricity configuration. You may not be able to make the repairs without a qualified electrician’s aid, but you can determine the root of the problem.

Multimeters are low-cost and available at most hardware stores. They are simple tools that measure electrical current. They have two prongs attached to a device that’s a bit bigger than a cellphone.

To test your breaker, set your multimeter to AC 120 volts. Touch one prong (the red one) to the hot wire at the breaker and the other to the ground screw located on the side of the box. The reading should be 120 volts or 240 volts. If not, then your breaker needs to be replaced.

Line Continuity

Often pool electrical circuits can run dozens, if not hundreds of feet, to reach the pool in your yard. The long length of the cabling means that there are more chances of something going wrong. When you’re checking line continuity, you will need a multimeter.

Do you have a junction box? It’s a box where electrical lines converge or split to various locations. Your problem could be in there. Set your multimeter to AC 120 Volts and check the line at the box. If it reads 0, you have a problem between the electrical box and the junction box.

If you don’t have a junction box or your multimeter test says there is no problem at your junction box, it’s time to check the lighting unit itself. Remove the light housing unit from its niche in the pool wall and remove the bulb. Place both prongs of your multimeter into the socket. If it reads 0, then your light fixture needs to be replaced.

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Final Thoughts

As you can see, there are simple techniques to employ when troubleshooting pool lights. The problem may be easy to fix yourself without the cost of a professional. However, if you are uneasy about working with electrical wiring and devices, it’s best to call an electrician or pool expert.

Questions about troubleshooting your pool lights? Let me know. Also, make sure to check out my design guide on pool lighting ideas.

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