trouble with a HUD cluster...

[2ndnissan]

I changed my dash today and was going to also change out the analog dash for the digital/Hud type(90 240sx). In the run position ,the speedo DID light up... so it seems the gauge works. The car just wouldn't START! I have a 5 speed and the car it came out of was auto. What is it that would keep the car from starting with that cluster installed. I switched back to the original and it started right up...