you people have no idea what your talking about, I suriously doubt anyone in here has ever picked up a wrench or a voltmeter. Its so ridiculous that one person has a problem and you'll come up with these crazy reasons for it happening. I feel sorry for ya diadpaku for having to listen to these people, but I really feel sorry cause whatever dealership (if it is a dealership and not some shady tree mechanic) can't figure it out.
Now that I have trashed everyone, let me tell you what your problem is. You need the electrical portion of the lock cylinder. And for those of you who don't know what it is, its the part in the steering column that turns when you turn the key on. Just go back to the dealer and tell them to install this part, it probably won't cost anymore than $200. And to prove my crediblity I work on these cars for a living and if you did take it to a dealer, tell them to get someone who knows what their doing to work on your car, cause it is a common failure with the same complaint always.
There you go, problem solved