How to Replace a Spa Light Fixture

In this post we will replace a faulty spa light fixture with a new one, covering all the steps necessary to accomplish this task.


Owning a home with a pool and/or a spa has many great benefits that far outweigh the bad, but one burden of such a luxury is the seemingly constant issues of ongoing maintenance.  Keeping the water in a good state of health by managing the chemical composition, skimming off leaves, grass, and bugs, cleaning filters, and keeping the walls and bottom free of dirt and debris to name a few.  Most pools and spas also have an underwater light fixture, and periodically the lamps will burn out.  I have covered the replacement of the lamps in two previous posts and videos:, and – but what happens if the pool/spa light fixture itself has failed for whatever reason, and now needs to be replaced?

In this post we will replace a faulty spa light fixture with a new one, covering all the steps necessary to accomplish this task.  My problem started out with a simple lamp replacement.  When removing the fixture from the niche, I found it to be full of water.  I attributed this to a gasket failure, so I replaced the lamp and the gasket and reinstalled the fixture only to have it fail again less than 24 hours later.  The fixture was again full of water and upon further inspection the body of the fixture itself had many tiny hairline fractures all around the circumference of the fixture.  My only theory is that the gasket developed a slow leak, allowing water to trickle into the fixture.  Halogen bulbs produce a tremendous amount of heat, and I believe that the small amount of water turned to steam causing an explosion inside the fixture with enough force to rupture the fixture body like this.  If anyone has another theory I’d be more than happy to hear it, but this is all that I can come up with to explain what happened in this particular case.  Regardless of why it happened, it did, and the fixture was now useless, and needing an expensive replacement.  My goal here is to show you how this is done.

Spa light fixture niches are cast into the pool or spa wall and connected with brass or PVC conduit to a junction box usually near the rest of the pool equipment.  The watertight fixture itself is a sealed unit that is designed to install into the wet niche, and comes with a long enough cord to reach the junction box in one continuous length.  To replace the fixture, we must disconnect the cable and wires from the source of GFCI protected power inside the junction box, attach a pull wire or rope to the cable (to facilitate pulling in the cable from the new fixture), and then out with the old, and in with the new!

Watch the video to see how this is done:

Now that the job is done, and the money is spent, what can we do to attempt to prevent this from happening again?  In my lamp replacement videos, I advise an inspection of the gasket, and if it seems good, still soft and pliable, free of any cracks or breaks, then reuse the gasket after replacing the lamp.  Now I’m not saying that a new gasket might not be faulty, and is always necessary when replacing the lamp, I now think that the $10 (approximately) to replace a gasket while changing the lamp is a cheap bit of insurance.  I don’t know if changing the gasket would have prevented this costly fixture replacement, but a replacing the gasket is something I will always do when replacing the lamp from now on.

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