Help with Digital DIC conversion

I have a 97 GT sedan that had the analog DIC. I bought a 97 GTP DIC and grafted it in using the charts that I have found on here and on clubgp. I managed to find all the wires and everything ok. All of the the door indicators and the low washer fluid thingy works perfectly. It even chimes me. I can't remember if my old one did that! The problem is that there are just flashing zeros all over the thing. I tapped into the UART serial data line. Can anyone lead me in the right direction? I read somewhere about tapping the VSS signal but I have no idea of where to find that wire to tap it. Please help. Thanks in advance.