Ignition/ theft deterrent system

Did you replace the lock cylinder only? I believe the theft lock sensor is in the housing that the cylinder slides into. It just contains a magnet. Are you wondering why it started?

Yeah I'm wondering why it started, As soon as the connection is made between the theft deterrent plug and the cylinder itself the car starts, without the key being turned. I did not replace anything. The ignition was taken out to bring to the locksmith so another key could be casted, as mine was worn.

I see what you are saying. The lock cylinder goes all the way in and locks into the housing, is the key still in the 'off' position?

yes

Does the key/cylinder rotate normally, in all the positions?

Yes. Other than the car automatically starting, I cant see anything else that doesnt seem right.

The only thing that makes sense, is the ignition switch is faulty. I can't explain why removal and insertion of the cylinder caused it to go that way. There is not much else involved. Looking at the procedure, you remove the ignition switch to access the release for the cylinder, is that correct?