Security Lockout?

What does the security light do when you try to start it? Usually if it is the immobilizer it will activate and stay on if it isn't detecting the key, or more common is that it will start and run about 3 seconds and shut off because of the pump disable signal. If it isn't doing that then I would suspect a bad pump, They tend to fail abruptly, and for some reason they love to fail on a full tank of fuel just to make the repair more fun. If it isn't doing the start and shut off there is a quick test that may show a bad pump, that is to go under the car and hit the fuel tank HARD a few times, then see if it runs, if so it's a bad pump. If the security light is on what does it do with the key off but in the ignition, what does it do when you turn it on, and what does it do when you try to start it?

Steve when I turn the switch to start, I hear a click in the ignition switch and it won't turn over. The only way if will turn over is jumping the relay but it just cranks, no start. Security lute comes on but does not stay on. I've checked fuses relays new starter.

OK, that description isn't the immobilizer. The light coming on and going out means it's reading the key. However it sounds like the signal from the ignition switch isn't making it to the starter relay. That signal also turns on power to the fuel system. Could you verify the vehicle for me. Year and engine please. That will allow me to find the correct wiring diagram so we can ID the correct parts. Thank you.

2009 Monta Carlo

There is a minor detail, the Monte was discontinued in 2007, Maybe the VIN would clear it up.