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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.  Avatar

    I have a Hayward T-546910 Wet-Niche and the voltage at the box is 120v and at the niche socket 68v. Niche bad?

    1. Matthew Simmons Avatar

      Yes, if the voltage is dropping that low, there is an issue with the cable. The likely solution will be changing out the light fixture and cable, not the niche though. The fixture might say “wet niche” but niche is referring to the plastic or metal housing/bowl sealed into your pool wall.

  2. BBQSamIam Avatar

    Hi. My pool has a Pentair LED light, about two years old. Just recently some of the colors seem to have stopped working, most notably red. When I set lighting color to red, barely any light is coming from the fixture. When i set it to white, it is now more of a blue color that emits rather than white. I have not yet gone through all of the colors, but these are what I have noticed so far. Any ideas?

    1. Matthew Simmons Avatar

      When an Intellibrite is having that kind of issue, usually replacing the bulb if not the whole light are your only options. Unfortunately, the bulbs are the same cost of a whole no light housing.

      The issue may stem from a bad board or something affecting the diodes. But to pinpoint something on that circuit board you will need more help than I can give. You may want to try the Trouble Free Pool Forum.

  3. Joe Pacheco Avatar

    My kaliedescope light works however the wheel isnt turning. It’s an inground pool and I dont think the white little button on the box (reset) is working either. Pool does light up but it’s stuck on one color. Is this fixable or do I need to consider spending $500 plus on another light? If so it’s gonna stay on green for awhile.

    THanks,

    1. Matthew Simmons Avatar

      What is the make and model of the light? Is this a Pentair Amerilite, Jacuzzi Full Moon or something else?

  4. Bob Watts Avatar

    With my multi-meter I am getting 120 Volts on my new pool light fixture at the light socket, but the bulb will not light. The bulb is new & I have also verified it works in another separate circuit. How can I be getting the correct voltage at the socket and a known goid nulb not light up?

    1. Matthew Simmons Avatar

      Are you sure you are screwing the bulb all the way in? If the bulb is the wrong shape, you may be screwing it in only part of the way. Though the light may seem like it is secure, the bulb is not contacting the socket.

  5. Sergio villani Avatar

    Looks like american products, but pentair purchased American products.
    I don’t want to damage by purchasing incorrect voltage on led light bulb, 12 volt or 120 volt. Also do not see transformer??

  6. Sergio villani Avatar

    Hi how can I tell if poollighthousing is 12 volt or120 volt, removed bulb housing old cannot read bulb voltage. Want to change bulb from incandescent to led thanks

  7. Rogelio Avatar

    Matt,

    I just replaced my two bulbs and gasket on AP light fixture, made sure to clean old gasket residue and cleaned lens. Everything worked great, but after a few minutes, I saw one of the lights keep on turning off and on and the other stays on solid. GFCI does not trip, fixtures do share same GFCI. Do you think I might have a bad bulb?

    I know for a fact the fixtures are wired seperatly. But use same GFCI

    1. Matthew Simmons Avatar

      Pull the light up on the deck, make sure the bulb is screwed in all the way. While it on the deck, test it to make sure the flickering has stopped.if the flickering persists, try a different bulb, switch to a different breaker, or any of the other steps mentioned in the article.

  8. Achilles Avatar

    My pool light gfci is tripping after about four minutes of the light being turned on. I reset the gfci and then light stays on for just about as long before it again trips. Any ideas please?

    1. Matthew Simmons Avatar

      Yes, my ideas are covered in the article.

      Test breaker, try different bulb, put light on different breaker, to name a few.

  9. John P. Avatar

    Hello Matt,
    I have a fairly good background in electrical circuity. And I am completely stumped on this one.
    I have a friend who just had a new pool light (120V, 500W pool bulb) and gasket installed in their 10 year old inground .They were told by the installer (after bulb and gasket replacement) that “the light would not turn on probably is a faulty switch”. They called me to come over and replace switch. before replacing switch, I did the usually troubleshooting. Using multimeter.
    1.Made sure power in was coming to switch , Check (120v). 2. Checked power out at switch. No power out.
    3. Replaced switch. (20amp single pole GFCI). Checked power in and out at switch,Check 120V. 4. Light not coming on ????. 5. Removed housing & light from pool. 6. Checked for power at light socket, Check 120 V. must be burnt out light. But just to make sure I told my friend to take the light and put it into a lamp socket inside to see if it lights up. It did ?????? Now what. POWER COMING IN ,POWER OUT TO SOCKET, POWER DISCHASRGE AT CONTACT IN LIGHT SOCKET, LIGHT LIGHTS UP WHEN TURNED IN COMMON HOUSHO;D SOCKET. ????? I’M STUMPPED.

    1. Matthew Simmons Avatar

      That is a good question and I am stumped as well. The only guess could offer is that the light cable is somewhat compromised. Maybe when you put the leads on the socket and it checks out but under the load of the light, it can’t handle it.

      But that is just a “just throwing it out there guess.”

  10. Jennifer Avatar

    Hi, I have a pool light that stopped working at the end of last pool season. We replaced the whole box this year. The lights worked for about 2 weeks then stopped again. We can hear the light running(the color wheel in the box turning) but there is no light. We replaced the bulb in the box but still no light. Any idea of the possible problem?

    1. Matthew Simmons Avatar

      What is the make and model of the light?

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