100W Pool light stopped working and wondering if fixture is bad ?

New, and have learned that these forums are very helpful with a wealth of knowledge.

I'm a Do-it-yourself guy, but somewhat new to pool maintenance/problems.

We have a typical kidney shape IG pool in South Fla. Recently the pool light just stopped working. Attacking the least expensive part first I replaced the bulb (100W). Afterwards, per instructions the fixture was submerged underwater, seal check..no bubbles and the light turned on. No luck :( it didn't light up. Thinking maybe it was a bad bulb I replaced it with another new bulb ... same results :(

Now I started to think, bad transformer. Not the case. I tested with my volt meter and I'm getting 12V at the fixture socket. So it's not the transformer. I've even cleaned the new bulb end and the housing socket with a brass brush. Nothing !

Now here's something interesting. I did notice that there is a wax type material at the base inside the fixture around the socket. I was told it should be clear or transparent looking. Mine has a brownish burnt look. Could that be the problem.. I'm confused because I'm still get a reading on my volt meter which should light the bulb. There should be contact with the bulb screwed in.... Grrrrrrrr !!

any suggestions would be greatly appreciated
Darrell