Pool Light Not Working

Pool lights live a double life: a lamp and a pressure vessel in one housing, sealed against the element it illuminates. Time attacks the seal, heat cycles attack the engine, and the GFCI watches over both with no sense of humor. Most dark-light calls resolve into one of those three stories, and the visible evidence, water behind the lens, a trip pattern, a dead twin comparison, usually names the story before a tool comes out.

Symptoms

• Light completely out with the breaker holding
• GFCI trips the moment the light switches on
• Condensation or water visible behind the lens
• Flicker or segments missing on an LED fixture
• Light that works cold, then dies as it warms

The costly mistake is impatience: resetting a tripping GFCI nightly trains an owner to ignore the one device installed to prevent a tragedy, and running a wet fixture corrodes it past rescue. A dark pool for one weekend is a nuisance; the alternative ledger is worse in every column.

Water and electricity make this the library’s most disciplined page: the checks are observational, the repairs are professional, and the GFCI is treated as a witness rather than an obstacle. The fixture that fills with water has announced a seal failure, not a bulb failure, and replacing bulbs into a wet housing repeats the expense on a schedule. Owners serve the repair best with the breaker off and the history written down. Note the weather in the history: fixtures that fail after storms or after deck pressure washing are reporting water intrusion paths, and sharing that timing with the technician changes the inspection from the bulb outward to the conduit and the niche.

Common Causes

Cause	How likely	What a homeowner can check
Bulb or LED engine at end of life	Very common	Note the fixture age and whether a paired light still works
Gasket failure admitting water	Common	Look through the lens for water, with power off
GFCI or transformer fault	Common	Use the GFCI test button once to confirm the device responds

Questions and Answers

Why does the light trip the GFCI only when wet?

It is always wet; the trip begins when moisture reaches electrical parts. Heat from running can shift water inside the fixture, which is why some lights trip minutes after switch-on.

Can the fixture be serviced without draining?

Yes, in nearly all cases. Fixtures carry enough cord to lift onto the deck, which is how gaskets and bulbs are serviced.

Are colored LED replacements reliable?

Modern LED fixtures are sealed, efficient and long-lived, and color models are a common upgrade at failure time. The niche and circuit decide compatibility.

Sources

• Florida Statutes Chapter 515, Residential Swimming Pool Safety Act