Latitude D820, D-Dock and line in

I have a tv tuner card in my D-dock's PCI slot. The problem I am having is that the audio from this card plugged into the mic/line in jack on my D820 is producing no audio. I have the jack set for line in, the volume on line in is all the way up and it is not muted. I plugged the speakers directly in to the tv tuner card's line out and did have audio that way. I also tried two different cables from the card to the line in jack. I still have no audio. Any suggestions?