ucrazymonkey

Have a 97 TA and installed a 01 Z28 stock Monsoon head unit in. After a day with it the battery went dead and when I jumped it now the radio is locked. How do I unlock it?
I believe I have the code but what buttons to push and where?

LS1 RULZ

From the FAQ thread over at LS1.com

"Theft-Deterrent Feature
THEFTLOCK® is designed to discourage theft of the radio. THEFTLOCK® works by using a secret code to disable all radio functions whenever battery power is removed.

The THEFTLOCK® feature for the radio may be used or ignored. If ignored, the system plays normally and the radio is not protected by the feature. If THEFTLOCK® is activated, the radio will not operate if stolen.

When THEFTLOCK® is activated, the radio will display LOC to indicate a locked condition anytime battery power has been interrupted. If the battery loses power for any reason, the radio must be unlocked with the secret code before the radio will operate.

Activating the Theft-Deterrent Feature
The instructions that follow explain how to enter the secret code to activate the THEFTLOCK® system. Read through all nine steps before starting the procedures.

If you allow more than 15 seconds to elapse between any steps, the radio automatically reverts to the time and you must start the procedure over at step 4.

Write down any three or four digit number from 000 to 1999.
Turn the ignition to ACC or RUN.
Turn the radio off.
Press the 1 and 4 buttons together. Hold them down until - - - shows on the display. Next use the secret code number which you have written down.
Press MN and 000 will appear on the display.
Press MN again to make the last two digits agree with your code.
Press HR to make the first one or two digits agree with your code.
Press AM-FM after you have confirmed that the code matches the secret code you have written down. The display will show REP to let you know that you need to repeat steps 5 through 7 to confirm your secret code.
Press AM-FM and this time the display will show SEC to let you know that your radio is secure. The LED indicator by the volume control will begin flashing when the ignition is turned off.
Unlocking The Theft-Deterrent Feature After a Power Loss
Enter the secret code as follows; pause no more than 15 seconds between steps:

Turn the ignition on. LOC will appear on the display.
Press MN and 000 will appear on the display.
Press MN again to make the last two digits agree with your code.
Press HR to make the first one or two digits agree with your code.
Press AM-FM after you have confirmed that the code matches the secret code that is written down. The display will show SEC, indicating the radio is now operable and secure. If the wrong code is entered eight times, INOP will appear on the display. You will have to wait an hour with the ignition on before you can try again. When you try again, you will only have three chances to enter the correct code before INOP appears.
Disabling the Theft-Deterrent Feature
Enter the secret code as follows; pause no more than 15 seconds between steps:

Turn the ignition to ACC or RUN.
Turn the radio off.
Press the 1 and 4 buttons together. Hold them down until SEC shows on the display.
Press MN and 000 will appear on the display.
Press MN again to make the last two digits agree with the code.
Press HR to make the first one or two digits agree with the code.
Press AM-FM after you have confirmed that the code matches the secret code that is written down. The display will show - - -, indicating that the radio is no longer secured. If the code entered is incorrect, SEC will appear on the display. The radio will remain secured until the correct code is entered. "