security question

friend has an alero...not sure of the year; anyway, it seems to have issues with security. Sometimes it will startup and run fine, other times the security light will come on and the car will not start. We sat there with the key on for about 10 minutes until the security light went out and then the car started right up. Is this how the security system on the car is supposed to work? I imagine there has to be something that is making the computer believe that the car is being stolen and preventing it from being started. Obviously a thief wouldn't sit in the car for 10 minutes waiting for the light to go out to steal the car, so I suppose that it's working, but why would the security keep the car from starting so often?

friend has an alero...not sure of the year; anyway, it seems to have issues with security. Sometimes it will startup and run fine, other times the security light will come on and the car will not start. We sat there with the key on for about 10 minutes until the security light went out and then the car started right up. Is this how the security system on the car is supposed to work? I imagine there has to be something that is making the computer believe that the car is being stolen and preventing it from being started. Obviously a thief wouldn't sit in the car for 10 minutes waiting for the light to go out to steal the car, so I suppose that it's working, but why would the security keep the car from starting so often?

Mine wound up having a bad tumbler assy in the ignition switch.

thanks for the reply!! Do you know if there's a way to test that without installing a new one?