I suspect the theft light is flashing on the dash??
If you didn't disconnect the battery before removing the cluster and possibly even if you did , the theft pats module probably decided this was an attempt to steel the vehicle.
Try the following procedure.
1. turn the key to the "ON" position, but do not attempt to start the vehicle.
The "THEFT" light will begin flashing rapidly (twice a second). After about 60 seconds, the "THEFT" light will stop flashing rapidly and begin a sequence of slow flashes (usually 1 blink, followed by 6 blinks).
2, Turn the key to the "OFF" position and completely remove the key from the ignition and hold at least two feet away from the steering column for 30 seconds.
3, Insert the key and turn to the "ON" position. Wait for the normal engine checking procedure to take place. The "THEFT" light should no longer be flashing. At this point you should be able to start the vehicle.
If the procedure above does not correct the no crank condition, you may be able to disconnect the battery for a period of 1 hr allowing the theft codes to clear from memory and the pcm to reset to a factory condition.
Then try to start the vehicle... If the vehicle will still not crank the pats may have disabled the pcm in which case you will have to have a certified dealer hook it up to a diagnostics machine to communicate with the pcm.
This is one of the most common issues with the for pats system as well as other vehicle makes.
I had a 98 caddy and every time I would wrench on it or jack it up I had to reset the theft system.
It would be nice if they gave you a scanner and you could just set a password to enter if you want to work on the car, or if you need to reset it easily .