Buick LaSabre 1999 security light

This is a very common problem on GM vehicles. The security system is notoriously known to fail. Basically when you insert your key, the system checks for a certain signal. If the system cannot get the correct signal from the key, it assumes the key is incorrect or you are attempting to hotwire it. The system then goes into SECURITY lockout mode. (prevents vehicle theft) This will either turn off the starter, or the fuel injectors. This has been happening with GM's for a very long time. There is a company called Newrockies inc. that sells a bypass for this online. Works great.

JUST DISCONNECT THE BATTERY FOR 10 MIN THEN RE CONNECT AND THE LIGHT GOES OUT.

@Buickowner1999 - This is what the manual says: "Universal Theft-Deterrent (If Equipped) If your vehicle has this option, it has a theft-deterrent alarm system. With this system, the SECURITY light will flash as you open the door (if your ignition is off). This light reminds you to activate the theft-deterrent system when leaving your vehicle. Activating the system: 1. Open the door. 2. Lock the door with the power door lock switch while the door is open, or with the remote keyless entry transmitter. The SECURITY light should turn on and stay on. 3. Close all doors. The SECURITY light should go off after about 30 seconds. The alarm is not armed until the SECURITY light goes off. If the SECURITY light comes on for one minute and then shuts off while the ignition is on, the security system has detected a problem with itself. See your dealer for service. If a door or the trunk is opened without the key or remote keyless entry transmitter, the alarm will go off. It will also go off if the trunk lock is damaged. Your vehicle's lamps will flash and the horn will sound for one minute, and then will go off in order to save battery power. Remember, the theft-deterrent system won't activate if you lock the doors with a key or manual door lock. It activates only if you use a power door lock switch with a door open, or the remote keyless entry transmitter. You should also remember that you can start your vehicle with the correct ignition key if the alarm has been set off. You must still shut off the alarm by inserting the key in the door lock, or by pressing the UNLOCK button on the remote keyless entry transmitter." Then it goes on to show how to avoid setting off the alarm by accident.