Here is how to unlock Delco Theftlock radio that displays "LOC"

[kl8ton]

Now you don't have to wait for a tech to respond, here is the 800 number, a dealer code and everything!

Taken from:
http://autoforumz.com/Pontiac-Help-u...pict40505.html

GM DELCO THEFTLOCK RADIO UNLOCK CODE:
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 him tell
you
to press "2" for Pontiac, press 206010 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 code...press 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.
There is an additional step you can take to remove all codes from the
radio and start from scratch by entering your own personalized 4 digit
code so that it won't get you in a pickle again! Just repeat step 4
and
you should get a display screen that reads ---. This means the code is
out, and you can now program your own code. Of course, once you
receive
the 4 digit code from the GM recorded message, just keep it in a safe
place, because you can use that same code again and again should you
have any more problems with it in the future. Good luck, and yes, it
does work.

[kl8ton]

Also, when I pressed presets 2 and 3 then pressed am/fm, the numbers were the same...so that CAN happen. I got my unlocked code and it worked fine.