Why won't my Sonoma start the security light is on

Security light means passlock or passkey failure. I have the work truck model without remote start. I have a passlock only system. If your key can be copied without dealer assistance and/or using a special blank then you have a passlock only system. You may have broken, detached, or shorted to ground wire coming from the key cylinder when replacing the radio. The purpose of passlock is to prevent the vehicle from running should a thief remove the lock cylinder. It may be as simple as fixing a wire problem or you may need to replace the whole cylinder to get back the original functionality or you may be able to bypass or fool the system in some way. I haven't had this problem yet so I can't give you a specific fix answer.