Lights in my pool are not working anymore. I have 12V (measured) feeding a Pentair submerged fixture. Took the bulb out and it had 0.3 ohms continuity. Measured the voltage in the socket and found 12V there as well. Took the bulb to the transformer and connected it directly to the 12V output and the light glowed brightly. But when I put the bulb back into the fixture, it doesn't light. Cleaned out the socket and the bulb to make sure contacts were good. I am at a loss. Any ideas?