Stop letting the GM dealers charge you $50-$60 or more to do this procedure that a five year old could do in less than five minutes! Here you go:

1. Press and hold presets 2 and 3 for about 5 to 10 seconds until you
get 3 digits on your display. This is the first 3 of 6 digits you will
need, so write 'em down.

2. After doing step one and writing down the code, immediately press the
AM/FM button to get the last 3 of the 6 numbers you'll need, and write
'em down. (if you wait too long between steps 1 and 2 and the LOC code
displays again, just start over).

3. Call this number, it's a prerecorded message, so don't worry about
having to talk to anyone...1-800-537-5140. The voice will ask if you're
calling for Chevy, Pontiac, Cadillac, etc... When you here,
press 1, followed by 02107 and hit the # key
. He'll ask you
for the 6 digit code that you've written down. Enter that and press the
* key. He will then give you a code, and the option to get additional 4
digit codes, but one should be sufficient.

4. Follow the normal procedure in your owners manual for unlocking the
radio with your new the hour set button on your radio until
you get the first two numbers of the code, then press the minute set
button until you've entered the last two numbers. Immediately press the
AM/FM button once the correct code is entered and the code SEC or
"secured" will be displayed on the display screen. Now, just turn the
radio on, and your ready to roll.