'02 Rendezvous - Audio System locked?

I bought a used 2002 Buick Rendezvous in September 2007 - 68K miles. There was a tail light out and also some of the audio system and a/c unit assembly lights did not go on at night. I discussed the tail light replacement with the dealer and it was no problem, he said to bring it in. So a week later, I brought it into the dealer where I was told they would replace the tail light (yippee! a 79 cent item) because it was a safety issue, but the cost to make the lights go on at night so i could see them would be over $800....i was like, what the heck? I was told it was one whole unit and the entire thing would have to be replaced. All along, I had thought I could just replace a fuse or something simple like that to make the lights go on. Fast forward to February 2008 now, and today the audio system read "LOCKED" and it will not come on. Are you kidding me? So I read the manual and it says that it is a theft deterrent that if your system is stolen a mechanism is activated so that the audio system will not work if installed into another vehicle. This is great news if it had been stolen. However, mine was not stolen, but now does not work. The manual says there is a secret code to punch in and if someone can tell me this secret code, i would be most grateful.

You might call a Buick dealership and talk to their service department.

There may be several good automotive stereo forums on the internet. The one I go to mostly is the12volt.com they have stereo information and Q&A forums also.