1972 240z electrical issues

[Zkid1994]

So, I'm having some problems with my rear, left side turn signal. When I use the turn signal to the left, sometimes the top light doesn't work, and other times, neither lights work for the signal. I know It's not a problem with the bulb or the ground, because both lights work when I turn on the hazard lights. I've taken apart the connections and cleaned them at all of the connections I can find. So what can I do? Or what is it that I'm doing wrong?
Thanks guys,
Ken

[evildky]

how are the bulb sockets? and the chassis grounds? if they all look good, look at the combination switch

[SBC 240Z]

Combo switch all the way. Mine did the same thing. Welcome to the 70s