Finally it runs sort of...
Do you have a schematic/wiring diagram? If so, have you confirmed that all of the "hot" circuits (pink/orange wires) are getting voltage? Are you using a stock 'Vette/GM instrument cluster? Wish I could give you a suggestion for the TAC module, but it's not used in my app, so I haven't really paid any attention to that...
If nothing else, this is good for a free "bump" for ya...
Verify on cluster connector C1 that B13 is a good ground and A14 has constant 12v, and A13 has run/start 12v
On the TAC, check pin 15 of C2 for ground and pin 7 of C2 for run/start 12v



