How turn off factory alarm on 1999 Chevy S-10?

To turn off the factory alarm on a 1999 Chevy S-10, first, try using the key in the driver's side door to unlock it, as this often disarms the alarm. If that doesn't work, insert the key into the ignition and turn it to the "On" position without starting the engine; this should reset the alarm. If the alarm continues to sound, disconnecting the battery for a few minutes can also help reset the system.