Hi, check to see if you have water in the light socket. My pool tech replaced my burned out bulb & did NOT replace the approx 1/8 inch rubber gasket. So it leaked. Later, I read everytime you open the socket to get at the bulb you need to replace the gasket w/ a new one. As a result, I had to replace the whole socket and wiring because of the leaky water in the socket where the light bulbs is located.

If you have to replace the socket and wiring make sure you can RE THREAD the wire back in the under ground pipe if you need to. I need to. I attach fishing in to the end of the wire so I could pull the new electrical wire back thru the under ground pipe.

I hope this works or gives you some ideas. Like I said, due to the water in the socket I had to replace the whole socket (say $200 socket & light)