:worship: Thank you so very much!!! I was racking my brain because I just got a 91' and that security light came on and I was like WooHoo!!! I have an alarm. I could get it to work. now I know why.:suspect:Maximln said:2dfx-There are 2 seperate theft deterrent systems that your car may have that share the "SECURITY" lamp. One is standard and the other one is optional. The standard one is the PASS Key system that utilizes that little black chip at the base of your ignition key. It operates like you describe--when you turn the ignition on, the "SECURITY" lamp will illuminate for a few seconds and then go off indicating that the system is operating properly. If the lamp were to illuminate during normal driving, it would indicate a malfunction in the system and the car may not restart. The system operates by measuring the resistance in that black chip utilizing wiring in the lock cylinder and an electronic module. If the correct resistance is measured, the vehicle will start. If an incorrect resistance is measured, the starter and fuel circuits will not operate and the vehicle will not start. The PASS Key system only uses the "SECURITY" lamp when the ignition is in the "ON" position. The optional system is the Content Theft Deterrent System. If your car was so equipped, it would use the "SECURITY" lamp when the ignition is in the "OFF" position. You can easily tell if your car is so equipped. With the car turned off, open any of the four doors and the "SECURITY" lamp should flash. If it does, you have this optional system. If it does not, your vehicle was not equipped with this option.
Hope this clears things up.
I know this thread is old but it helped.