Thanks guys, I've pulled my grille off and I see the purple and black wires. I probed both wires from the grill area back to the light socket and they both had good continuity. What could cause it not to light up if the connection is good from the grille?
Also, I was looking at my ball and socket pieces and they're a bit rusted. I pulled one off and it's definitely not brass like the one in the photo on delorean.com...