Troubleshooting Problems with Underwater Pool Lights

bright lights underwater in tiled pool
  • 1 hours
  • Beginner
  • 0-50
What You'll Need
Phillips head screwdriver
Tape (optional)
What You'll Need
Phillips head screwdriver
Tape (optional)

Owning a pool is a status symbol. It's something to show off and something to enjoy. When you have a pool, you have a place to exercise by swimming laps. You have a place to have fun by splashing around. You have a place to cool off in the summer sun, a place for friends to gather around, a place you're proud of. Until, that is, one of the lights in your pool goes out. Now what the heck do you do?

What Next?

A broken swimming pool light feels like a major hassle immediately. After all, the darn thing is underwater. How can you access it safely? And once you figure that part out, how do you even fix a pool light, anyway? It's easy to end up getting overwhelmed by what is essentially a pretty small problem. So how can you deal with this small problem without it turning into a big deal?

First things first, don't start draining the pool. This step isn't always necessary when you're fixing a pool light, so don't jump ahead and start taking unnecessary steps.

You do definitely need to go turn the power to the pool lights off at your main circuit breaker. Make sure this circuit breaker stays turned off the entire time you're troubleshooting your pool light. It goes without saying that electricity and water together are an extremely dangerous mix and a potentially fatal combination.

The next thing you need to do is go to your circuit breaker box. The problem may be as simple as a breaker that has tripped, which means it shuts itself off. You may only need to literally flip a switch. Look at your breaker box. Every switch should be pointing in the same direction. If you see one that isn't, flip it! This might fix the problem. If it doesn't, the real troubleshooting can begin.

pool light shining in water

Test the Circuit

If the circuit breaker was "tripped," or flipped the wrong way, flip it back. If it trips again immediately, this means you have a short circuit. You will need to have a professional electrician fix this problem. For them, it's a fairly easy fix. But if there is no tripped breaker, you can proceed to check the next item on your pool light troubleshooting list: the GFCI.

Testing the Circuit Interrupter

The GFCI, Ground Fault Circuit Interrupter, is an especially sensitive circuit breaker. It will trip, or shut itself off, if it detects even a tiny electrical current going to the ground. What does that mean? Basically, that means it's designed to shut itself off to prevent people in the pool water from being electrocuted.

There are a few places where the GFCI may be located. You may find it in the main circuit breaker box for your home. This may also be located inside a subpanel box that's near the pool itself. You can even find it at an electrical outlet near your pool, sometimes.

Once you figure out where your GFCI is, check it to see if it's been tripped. If it has, flip it back into position. Now, push the test button. You should hear a popping noise. If you don't, push the "reset" button. if the circuit trips, you have an electrical problem. Call an electrician to get this resolved. But if the circuit doesn't trip, go back to your breaker box and turn your pool lights on.

gfci receptacle plug

This may solve the whole problem. Sometimes, a little bit of water can get inside the light fixture. The light heats the water, which evaporates. This will cause the GFCI to trip. humidity alone can cause this breaker to trip because it's designed to be very sensitive.

If the GFCI trips again once you turn the pool lights on, then you probably still have water inside your light fixture. If the GFCI does not trip but the light is still not turned on, the most likely problem is a burned-out bulb. In both cases, you need to pull the fixture from the pool in order to continue your troubleshooting process.

Removing the Light Fixture

Go ensure that your circuit breaker to the pool lights, the GFCI and the switch for the pool lights are all turned off. Double-check. This is one step you don't want to skip no matter what. If there is any possibility at all, no matter how remote, that someone might flip any of these switches put tape over them so they can't be easily flipped. The tape will serve as a warning to anyone that work is being done.

Now the real work can begin. You'll need to go to the faulty pool light and unscrew the pilot screw holding it in place. This is a small screw that usually has a Phillips head. The screw will be positioned near the top of the fixture. There's another set of screws in a circle around the light. For now, you just want to locate the pilot screw and unscrew this.

Once the screw is loose, you should be able to slide the fixture up and out of the pool. If you can't find a pilot screw, your light may be held in place with a clip. You'll need to use the screwdriver to pry the light out of the pool. However, make sure there is no pilot screw before you start prying or you could end up breaking something.

Pool lights are designed to have water inside the niche where they sit in the pool. This helps keep the light cool and this is why you can remove the light fixture even while there is still water in the pool.

Sometimes, the cord attached to the light may not be long enough for you to fully remove the fixture from the pool. This is a poor wiring job. After you cuss about that a little, go to the junction box that the cord is connected to. Disconnect the cord at the box and tie a piece of strong string or wire to it so you can pull the cord back into place once you're done.

Examining the Light

underwater pool light with cover removed

Once the light is removed, you can open it up. You will likely see one of two scenarios at this stage. Either your light will have several screws around the back of the rim or it has one scream with a band clamp holding the fixture together. Remove the clamp or the screws and pry the light open. Work slowly and carefully. You want to open the light, not break it. Take special care with the lens of the light, as this is a sensitive area.

There may be water inside the light, which you'll want to dry out. A towel and hairdryer will work fine. Remove the bulb and dry the entire fixture thoroughly. Don't touch the bulb with your bare hands. The lifespan of halogen bulbs can be greatly reduced if they come into contact with the oils in your skin.

Once it's all dry, try to turn the light on very briefly. Don't let it stay on longer than a few seconds, if it comes on at all. These lights are meant to be water-cooled, so they will get very hot. If the light doesn't come on, the bulb has burned out. Replace the bulb and test it again.

If the light comes on in either scenario, put the fixture back together again. Replace the light gasket. This can never be properly put back the right way once it's removed, so you'll need to use a brand-new one. Make sure the fixture is put together tightly.

Hold the entire light fixture under the water of the pool and look for bubbles. If you see them, repeat the process by pulling out the fixture and reassemble it.

Put the fixture back into its niche. Screw in the pilot screw or snap in the clip to make sure the light is secure.

if you disconnected the cord at the junction box, now's the time to put the cord back.

Next, go around and flip on all your breakers and your switches. The light should be working normally again!

When Troubleshooting Fails

If you do all of this or you have a pool light that's extremely different from the standard style, you will need to get outside help. If you're determined to try to DIY this project, you can always contact the pool manufacturer or look up your specific pool model online and try to get more specific instructions for the exact type of pool light you have. Otherwise, you can always call the calvary -- which in this case is an electrician.