Your security lights are probably blinking because you tripped up the fuses located under the steering wheel harness. Check the fuses to make sure they are fitted tightly and in good working order.
Gm has a high failure rate of the passkey security system. I would suspect the ignition/passkey switch will need replacement. This will likely need a professional repair.
It may be due to incorrect ignition system. Verify whether the key is original with the dealer. Also it may be due to corrupted pass lock system. To rectify it you must on the ignition for ten to twenty minutes . After that the vehicle will start.
You can do it yourself but it is going to be tricky to get to. You may need to pull the starter off or the alternator off to be able to get to it. It is only two bolts holding it on but again it will be tricky to install.
You need to program the passlock system in your vehicle. Follow these steps: Leave the ignition on for 10 minutes. Turn off and repeat for another 10 minutes. Repeat again. Your car should now start.
