2004 Ford Focus ZTS Air Bag computer reset

Hello, everyone, I have a 2004 Focus ZTS that received a moderate frontal impact, my air bags did not deployed but, my seat bealt did, after i replaced the seat belt and checked the sensors everything seem to be in good shape, but my air bag light stayed on.
I took it to the ford dealer and they said that the SRS computer was bad, so i bought a new one.
Now, i have installed many SRS computers before on different cars and i never had a problem ( just "plug and play" basically) but on this one is not working, with the old SRS unit the light would blink slowly and then stay on but with the new one it just blinks very quickly.
Does anybody knows what is going on or how to program it?
Thank You.