To make the radio of a 1999 Pontiac Montana work after it has been disabled by a battery disconnect, you will need to enter the radio's security code. This code is typically found on a small card that came with the vehicle when it was new. If you do not have this card, you can contact your local Pontiac dealer and they may be able to provide you with the code.
Once you have the code, follow these steps to enter it into the radio:
1. Turn on the radio.
2. Press and hold the "CD" button for at least five seconds.
3. The display will show "CODE".
4. Enter the security code using the preset buttons.
5. Press and hold the "CD" button again for at least five seconds.
The radio should now be unlocked and working again.
