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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. Eli Avatar

    Hi Matt
    When I switched my pool light on, it through the breaker. After resetting the breaker, power was restored to the control panel, all readings were working, but the filter would not turn on, nor would the sweeper pump.
    I tried the light switch again and again it threw the breaker. Neither of the pumps will turn on, even with the breaker reset.
    Is this a safety feature requiring the light to be fixed before I can run my pump?
    Thanks

  2. Bill Avatar

    Hello –

    We have Hayward Color Logic lights installed in our pool, 2 of them. Everything worked fine until a few days ago when they went out of sync. Then one of the lights started blinking, just blinking. The pattern is 3 red blinks, quick pause, 3 red, quick pause, 3 quick blue blinks. Any ideas? Maybe that’s code for “congrats, time to by a new light, you’re poor again.” Then again, maybe not. Any assistance would be appreciated!

    Thanks

    1. Matthew Simmons Avatar

      Unfortunately, your codebreaking skills are spot on. It’s time for a new light. Even though I like some of Hayward’s other products, their ColorLogic lights seem to prematurely quit.

      You have a couple of options when it comes to replacing the light. First, you can replace the single light with another ColorLogic to ensure it syncs up with the other bulb. If you want to get away from the Hayward, we suggest the Pureline PureColors or the Pentair IntelliBrite. Both have better track records that the ColorLogic.

  3. Matt Avatar

    I’m hoping someone can solve this one for me. I have an inground pool with a light. The previous home owner showed me which switch controlled the light, and a couple of years ago the switch seemed to work ok. It would change colors when I turned it on and off, and eventually once I got through all the colors it would go off. And then one day I couldn’t turn the light OFF with the switch anymore (but I hadn’t used it in a year, so I wasn’t sure if I was forgetting something)! It also doesn’t change colors when I turn it on and off – in fact the switch doesn’t seem to do anything.

    It’s attached to GCFI, so I just have turned it on and off using the GCFI for the last couple of years. The pool light is ON (and white) when I turn the GCFI on, and OFF when I turn the GCFI off, regardless of whether the light switch is on or off.

    I don’t know if this is a weird pool light issue or more of a question for an electrician, but it seems like somehow the GCFI has bypassed the light switch all together? Or there’s something weird with the pool light switch I don’t know about.

    The only reason I care is that I finally sprung for a robotic cleaner and now anytime I want to clean the pool I also have to have the light on, since the outlet near the pool is also run by that same GCFI.

    Anyone have any thoughts about if there’s maybe something else that could control that light…or if you think it’s just a bad switch and I should try to change it out?

    Thanks!

    1. Matthew Simmons Avatar

      For an answer on this, you may try posting this over at Trouble Free Pools. It is moderated by a few electricians I believe. if they can’t help, then it would be time to bring in an electrician.

  4. Wayne Avatar

    We just had our pool and spa resurfaced. Afterwards, the pool light would not work. I replaced the bulb and it works fine. So does the spa light. However, they will not work at the same time.

    Last night we had the pool light on then turned the spa light on and they both went off. Turned the two switches off for 5 seconds or so and each of the lights come back on separately, but when turning them back on together, they stopped working again.

    No breaker reset needed. Just 5 seconds to turn the switches off and back on. No water in either housing and both fixtures are secure.

    Where should I start?

    1. Matthew Simmons Avatar

      I’m perplexed by that, I do not know what is causing this delay. You may want to try asking this question over at http://www.TroubleFreePool.com

  5. Rich Martin Avatar

    Matt- I suspect the simplest of a burned out bulb, but my fixture has 5 screws not 1 like all the videos I’ve found. Just remove all 5?

    1. Matthew Simmons Avatar

      I guess, but it’s hard to tell for sure, because I can’t see it.

  6. Glen Avatar

    Hi, I have Hayward Astrolite underwater fixtures. One in my pool and one in my spa. The one in the spa comes on with no problem but when i try to turn on the pool light it trips the GFCI. I reset the GFCI and turn on pool light and it trips again. but the spa light works fine as long as i don’t try to turn on the pool light.. Any suggestions on what to do?

    1. Matthew Simmons Avatar

      GFCIs can go bad. If it has become more volatile/sensitive recently and you have not altered the wiring, then this may be a sign that it needed replacing.

  7. Spi Avatar

    Hi, my 120v 300 watt bulb burnt. Store mistakenly gave and a 12v bulb. Installed it, turned on, fried bulb. Got a new 120v bulb, won’t work, Cant find a gfci, all breakers at panel have power. What to do??

    1. Matthew Simmons Avatar

      Test the voltage at the light socket.

  8. Kevin Avatar

    My spa light turns on and off randomly. It is on the same circuit as the main pool light which seems to be fine. The breaker does not trip. What should I check?

    1. Matthew Simmons Avatar

      We cover a few other things to check in the article.

  9. GFD Avatar

    My 1.5 year old Hayward colorlogic LED only illuminates a dim red despite cycling on and off. Also, when the power switch is turned off the light remains on and slowly dims until it shuts off after several seconds. Any thoughts on problem?

    1. Matthew Simmons Avatar

      There is not much you can do with a ColorLogic once it begins to fail like this. The unit is sealed and Hayward does not offer replacement parts. the usual fix is replacing the whole light.

      Regarding a replacement light, you have a few options. If your light niche is a standard size, which is usually about 8-10 inches deep, you can install a Pureline PureColors light. These are great because they use a Pentair Amerilite housing with a PureLine PureColors screw-in LED bulb. So if your bulb were to ever fail, you just install a new PureColors bulb, without having to replace the whole fixture. Or if you want to stick with the same style of LED light but a different manufacturer, there is alway the Pentair Intellibrite.

  10. Richard Avatar

    I have a Hayward LPWUS11100 LED light fixture in my pool. It is the only light i have in the pool. Its about 1.5 years old. Recently when i turn it on, the light will shine brightly for about 30 seconds then go dim (still on just not as bright) for about 30 seconds and then back to bright again. This will continue as long as I have the light on. Any thoughts on what might be causing this or how to diagnose?

    1. Matthew Simmons Avatar

      Use a multimeter to test the voltage of the power source. There is not much else I know you can do with those types of LED lights. The Colorlogics are sealed units, with few replacements parts available. You may want to give Hayward a call for troubleshooting help, because this specific issue is not mentioned in their manuals.

      The closest thing they come to mentioning this problem is below:

      PROBLEM: Light will not come on or light cycles on and off.
      SOLUTION: Depending on cord length and operating voltage, automatic thermal switch may be cycling due to excessive air/pool water temperatures (over
      105ºF). Temporarily switch to a cooler color (Deep Blue Sea, Royal Blue, etc.) until air/water temperatures cool off.

      1. Richard Avatar

        Thank you Matthew. I’ll check out the voltage and see if its fluctuating at all. If it is then, i’ll replace the transformer hopefully avoid the costly LED replacement. If everything seems normal then i guess I’ll just have to bite the bullet and get a replacement. Appreciate the quick reply.

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