It might make it easier to see what's going on if you remove the assembly from the dash. The housing collar behind the dash unscrews simply by twisting it, and then the lighter and socket will come out of the dash.
Since there are two wires going to your cigarette lighter, there's a possibility it is back-lit like the one shown here.
http://67-72chevytrucks.com/vboard/s...=Lit+cigarette