Unlocking a Radio That Displays LOC When Code is Unknown

IMPORTANT: Starting in 1995, a factory back-up code can be used to erase the original code if it is unknown.

Have account number ready to enter when asked. Account number is your 5 digit dealer code followed by one of these numbers:
^ Chevrolet - 1
^ Pontiac - 2
^ Oldsmobile - 3
^ Buick - 4
^ GMT - 5
^ Cadillac - 6
^ GM Canada - 7
^ Saturn - 8

IMPORTANT:
^ Read all steps before starting the procedure.
^ If more than 15 seconds elapse between any of the steps, the radio automatically reverts to time and you must start the procedure over from step 1.
^ In order to unlock the Theftlock(TM) system when code is unknown, perform the following steps:

1. Press and hold push buttons 2 and 3 until a 3 digit code appears on the display.
2. Write the 3 digit code on a piece of paper.
3. Press the AM/FM push button, a 3 digit code will appear on the display again.
4. Write the 3 digit code on a piece of paper.
5. Call Delco Electronics at 1-800-537-5140.
6. Follow the computer prompts to obtain the back-up code to be used in place of unknown code.
7. Press MN and 000 will appear on the display.
8. Press and hold MN until the last 2 digits agree with the back-up code.
9. Press and hold HR until the first 1 or 2 digits agree with the back-up code.
10. Press the AM/FM push button after you have confirmed that the code matches the one you wrote down. If REP appears on the display, repeat steps 7 through 10.
11. The display will show "- - -" to indicate unknown code has been removed.
^ If the back-up code does not unlock the radio, try reversing the first and last 3 digits of the display code.
^ If this is unsuccessful, call Delco Electronics to obtain a new factory back-up code.