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Tips for Troubleshooting Your Pool Light

A glimmering pool light will add dazzling high notes to your poolscape; but a dim or broken light can leave you in the dark as to how to fix it. When your light goes kaput it is time to roll up the shirt sleeves, pull out the test probes and go to work.

But where to start? That is a tough question, as a pool light can have a hundred or so feet of cable, circuit breakers, GFCIs, and junction boxes to contest with. I’ve learned to start with the easy and then work your way up to the hard. We will walk through some simple fixes and some not so simple.

So, sit back, relax and let us enlighten you. I swear that is the last pun in this blog…

What’s the bright idea? (I lied)

The Easy

Loose Fixture

A pool light, despite all its waterproofing and hundred or so volts of electricity, is held into the pool wall by one bolt called the lockscrew. The lockscrew is located at the 12 o’clock position on the light fixture face. If the fixture wobbles when touched or a strong ripple hits it then a loose screw is likely the cause.

Lockscrew

To fix the issue, dip into your pool with a phillips head screwdriver and tighten the screw. If the screw is stripped or lost, make sure you replace the screw and the gum o-ring.  The o-ring is important to prevent excess water leakage into the niche or housing.

Leaky Pool Light

For the close observing swimmer, you may notice water in the light fixture. Most of the time, this issue is not discovered until the bulb blows. As we all should know, water and light sockets do not mix.

A leaky pool light stems from a bad lens gasket. This part is also called the housing gasket. The heavy gauge rubber ring acts as a clamp seal that waterproofs the joint between the lens and light housing. Chlorine exposure or old age can deteriorate the rubber to warp so that it allows water to reach the light internals. A fixture filled with water can also cause a breaker to trip, so be mindful of that when troubleshooting. Replacing a pools light lens gasket is pretty simple and even the more novice pool owners can do the job.

POOL LIGHT LENS GASKET
Pool Light Lens Gasket

Another less likely cause of a pool light fixture leak is a power cord conduit seal leak. If the conduit seal degrades to that point, the light is likely dead and will require replacement.

Change the Bulb

If your pool light will not turn on and you suspect the bulb, the old shake test is simple enough for  any pool owner to do. The steps on the bulb shake test are simple: remove the light bulb from the fixture and shake it next to your ear. If you hear the ring-a-ting-ting of a broken filament then it’s time for a new bulb.

If the bulb was relatively new before it blew, I would not run out and replace it right away.  A test of the circuitry may be necessary to be certain the new bulb will not be ruined by a power surge or some other electrical issue.  Take a look at our guide on replacing a pool light bulb.

The Not So Easy…

Tripping the Breaker

The dreaded CLICK of a tripped breaker is an annoying and sometimes befuddling event. Annoying because most of the time the reason for the trip is a mystery, unless of course you just plugged in an appliance that overloaded a circuit.

Before we do anything, we want to reset the breaker and also restore the circuit to the point before the trip. To perform the latter, we will unplug any appliance that may have immediately caused the overload.

Next, we will reset the breaker at the box. When a breaker is tripped, it flips to an idle position and will not resume current flow until it is completely reset by hand. To reset the breaker, find the flipped breaker, push it to the complete off position and then flip on. If the switch is not completely reset, it will spring back to idle. If you correctly reset the breaker but it continues to flip to neutral, replacing the breaker may be necessary.

TRIPPED BREAKER
Tripped Breaker

Bad Breaker

The actual task of checking the breaker is not the difficulty, mainly because the task consists of touching a couple probes to terminals. The usual hurdle homeowners have to overcome is getting a multimeter to complete the task. Your run of the mill meter can be found at a local hardware store or borrowed from friendly neighbor.

To test a single pole 120 Volt breaker we will need to remove the front panel of the breaker box to access the terminals. Before removing the panel, make sure to mark the switch that handles the light’s load.

The multimeter will have two leads: one Red lead (positive) and one Black lead  (Negative or Ground.)The black lead is connected to COM port and the red to the mAVΩ port, the latter will be touched to the “hot” wire to measure volt load. Set the multimeter to read 120 Volt AC or higher so it can accurately read your breaker.  Touch the red lead to the single pole terminal and the black lead to the neutral base row. The neutral row is normally labeled, but if it is not look for terminal row with the white wires.

Tripping the GFCI

The ground fault circuit interrupter, better known as the GFCI is a safety device used on installations with a higher than normal risk of electric shock. Most homeowners are familiar with GFCIs from their bathroom electrical sockets. The socket GFCI are also used on construction sites where machinery cords could come into contact with water or sheared.

GFCI BREAKER
Gfci Breaker

The GFCI works by reading a circuit’s current for an irregularity that could be a symptom of a shock hazard. A GFCI circuit can be activated by a current change as low as 4 milliamps. Interrupter switches are an absolute necessity for safety at home or work, but that sensitivity can cause a nuisance, quite literally.  A phenomenon known as nuisance tripping occurs when a GFCI trips when it mistakenly reads a current change as a potential shock hazard.

Common triggers of nuisance trips are:

  • Circuits longer than 100 feet
  • Lighting circuits using fluorescent bulbs
  • Permanently installed electric motors, i.e. bathroom exhaust fans

If the above do not apply to your tripping circuit, it may be time to replace your GFCI. Like any electronic component, these interrupter switches have a lifespan and need to be tested monthly to determine their status.

Line Continuity

A pool light may have up to 200 feet of wire running from the power source to the fixture. Within that length of cable, there may be a fault in a junction, the line or the fixture. Checking line continuity is the process of finding the source of a fault in circuit. Again this task can be done with the handy dandy multimeter. We will be starting from a point in which we assume you have already checked the GFCI and breaker as mentioned earlier in this piece.

  • Set the multimeter to read for 120 or 12-volt range for proper readings.
  • Measure line voltage at junction box. A junction box is the point at which multiple electrical device cables can be joined to one main line. Not all applications utilize a junction so this step may not apply.  If the junction reads 0 then the mainline leading to box is malfunctioning. Have an electrician inspect and install a new main line from box to breaker.
  • Remove fixture from niche, then remove bulb from fixture, touch multimeter leads to fixture socket for reading. If the meter reads 0 from the socket, the fixture is dead and needs to be completely replaced.

As you can see the testing of a pool light is straightforward due to the simple nature of its design. One electrical circuit to the fixture allows for a relatively easy troubleshoot without hard labor. As with anything electrical, if you have any questions or reservations, ask a professional before fiddling with live wires. A working pool light is not worth risking electrocution.

author avatar
Matthew Simmons Technical Writer & Pool Product Expert
Swimming pool expert at InyoPools and host of Poolside Chat, brings over a decade of experience in the pool industry.

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279 responses to “Tips for Troubleshooting Your Pool Light”

  1. Tampa Sam Avatar

    Hey Matthew

    I have a 4- year old pool with 8 LED lights. Every light has filled with water and needs to be replaced. Two lights have filled with water and been replaced multiple times, with one light having been replaced 4 times in 4 years. Am i just having bad luck or is there possibly something more systemic going on. the lights are all Pentiar.

    1. Matthew Simmons Avatar

      That sounds like bad luck. Gaskets should not fail at that rate, unless they are dealing with severe water conditions, like super high chlorine levels

      1.  Avatar

        thanks Matthew. so they had to do an acid wash shortly after the pool went operational, would that have damaged the gaskets?

        1. Matthew Simmons Avatar

          Muriatic acid is a very corrosive liquid and could have easily damaged the light fixture if left to set on the housing.

  2. Koko Avatar

    My pool lights have stopped working. They are multicoloured LED light types. I normally operate them via the chlorinator go App. Once I switch them on, I get a buzzing noise on the control panel but the pool lights won’t come on. I can’t find any GCFI panels and there’s no trip on my switchboard. The pool pump controlled from the same panel works just fine.

    1. Matthew Simmons Avatar

      Some things I mention in the article to check: Have you checked to see if there is water in the light? How old are the lights? Have you tried switching the lights to a different breaker to determine if there is an issue with the light or the breaker?

  3.  Avatar

    when testing ohms in your pool light. what will your meter read when there is water in the fixture

    1. Matthew Simmons Avatar

      First, you shoudn’t be testing it when there is water in the fixture. Let the fixture dry out, then check the voltage at the socket.

  4.  Avatar

    I noticed that there is some water inside one of my pool lights. Is it dangerous to swim in the pool with the lights off?

    1. Matthew Simmons Avatar

      If the water reaches the socket or any part of the circuit the GFCI should trip ending any chance electric shock. But you may just want to turn it off at the breaker as a preemptive measure.

  5. Jodi Delmer Avatar

    Hi Matthew,

    I had my pool re-plastered. They redid all my pool/spa light gaskets, and they worked. within 24 hour of my pool being filled with water my spa light fixture filled half way with water. They came out and replaced the gasket again, but still the same problem (half filled with water (visible water line)). Now they want me to buy a whole new light fixture and charge me to replace it. Is it the fixture? Or is it more likely that the gasket was put back on wrong? The light worked just fine until they touched it. I’m just having problems with believing that I need to spend another $500. Advice please.

    1. Matthew Simmons Avatar

      I think they were just doing something wrong with the gasket installation, there is nothing during the replastering process that I know of that is going to cause the gaskets to go bad that quickly.

      1. Jodi Delmer Avatar

        That was my thoughts too. I will try to replace the gasket on my own. I find it hard to believe that two gaskets would be bad as this is their job, but maybe they are just trying to get more money out of me. Thank you for the insight and your time and consideration.

  6. Cathy Avatar

    Hi!
    My pool is two years old. I have 2 Hayward led lights,one pool, one spa. Separate breakers but same on off button. Spa light won’t come on. Breaker not popped. Should I start with warranty replacement with Hayward or check the transformer. No evidence of Water in bulb. Not sure how long the warranty is from Hayward
    Thank you!!

    1. Matthew Simmons Avatar

      Check the transformer. If the transformer checks out, then see if the light can be replaced via warranty.

      1. Randy Avatar

        Just. Recently moved into a home. With a. Pool. Light turns on fine but after about ten minutes the light starts blinking on and off…?

        1. Matthew Simmons Avatar

          Welcome to the blog, this is a great place to start your research on how to troubleshoot your pool light circuit. Give the article a read and post a comment after you have completed troubleshooting if you have any further questions.

  7. Unknown Avatar

    My pool light is floating on the water is it dangerous

  8. Jon Avatar

    I have the Pentair 5G 12V LED lights attached to my EasyTouch 8. Two lights in pool. One in spa. Each on separate circuits obviously with separate 12V/100W transformers. Spa light suddenly stopped working. Come on sometimes but usually not. Sometimes it comes on one color and just flashes. I’ve pulled the light and see no water inside. I’ve yet to pop open circuit breaker boxes but I can hear the relay in EasyTouch clicking and I feel it at the transformer. These lights are about 3 yrs old. Any thoughts as I stumble through the weeds? I have lots of electrical experience but not pool lights. I’m the one who put them in. Oh what fun that was. Attached nylon rope to old light wires, applied pool grease, pulled very carefully. Attached new wires to rope I pulled through, greased it, slide back through. Not so tough when the run is 10-15 feet away. The one must have gone around the world and back. Straight line to junction box is about 30’. Had to use a 75’ light. Good thing I measured the old cable before buying the new one. I was going with a 50’ until I realized how long that run. Talk about holding your breath if it gets stuck or the rope comes off somehow. Just my experience in case anyone benefits. Right now just need my spa light back to 100% without having to buy and expensive LED board.

  9. Mike A Avatar

    Matt,
    About 2 months ago I replaced my pool light with a LED color changing bulb. It had a regular flip light switch. I decided to have an electrician install a Wifi switch for convenience. The old light worked just fine. When installing the new WiFi switch the breaker would continue to trip. Finally found one that worked without tripping the breaker but I noticed when I turned the light on that it was flickering very fast. We pulled the pool light out and there was a little bit of water in the light. The fixture was installed in 2005. Is it possible that it is a breaker issue or is it pretty much a slam dunk that the fixture is fried. We tested the existing fixture with a light bulb and it pops the breaker instantly. I guess my questions are, why did it flicker with the pool light but once we pulled it out and used a test bulb it trips right away. The second is is it possible that it’s just a coincidence that all of this happened when switching the light switch out.

  10. Ross L Avatar

    Hi Matt,

    I have an intellibrite underwader pool light and it is stuck on Red only? When I change to another color that color comes on for a second but then switches to solid Red. Any ideas?

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