No sound from earpiece on iPhone 3G?

Hello all,

Just replaced the display assembly which seemed trivial enough. I've actually had to replace the glass in the past and since I would up supergluing pieces together I had replace the entire display unit. This is much easier.

Everything works except the earpiece. The speaker, touchscreen and voice microphone all work, but nothing from the headset. Any opinions on whether I have a cable seated wrong, or did I get a defective "display unit"? Any thoughts out there?

- LT