Cadillac Repair: 1990 cadillac sedan deville 4.5, cadillac sedan deville, lock cylinder

Question
it will not start and the security light stays on. I seen that you said i may need a ignition lock cylinder in order to read my chip correctly. I was wondering if there is anything else I need because i previously changed the steering column which didn't help?please offer your advice before this event gets any more expensive.

Answer
Your ignition key has a code embedded in the chip on the key and if the code on the key does NOT match the identical code in the start module the car will not start.

Your dealer has the key and module code reader in order to see if they match or you could have a wiring problem.