overhead console problems

This console has been a project for nearly 3 months now. So far, all the lights and homelink work perfectly. I've installed a "mode" computer overhead console out of a 97 bravada into my 1996 Jimmy. Everything functions as it should... For about 10 seconds. My compass always reads a "C". The temperature and stats display accurately, but then I get the dreaded dashes (--).

I know it must be the vss signal. I've soldered, wired, and verified my connection from pin 3 of the black connector is properly in contact with the computer. I put an 25A inline fuses in all of my wires (except for temp sensor); including both my vss and serial data wires.

I know others have had these kind of problems. I've tried 3 different display computers with no luck. I've scanned through all of the forums. There must be some compatibility issues. BlazerLT, you're my only hope!

If anyone has any wiring questions... I can help! However, mine is not fully functioning yet...