I had a problem with the steering lock, which is a T shaped piece of metal with the lock cylinder on one side and the ignition swicth on the other. A piece inside this T broke off, so when you turn the key nothing would happened. The key buzzer switch is in attached, or in the inmediate vecinity of this piece, and may be that is the buzzer that you hear.
I suspect either the steering lock or the ignition switch itself.
You have to remove the lower dash part of the dash to get access to it. Again, that is based on my model year. Yours may be different.
Good luck!
