What makes the security light come on in a 2001 bravada won't start?

In a 2001 Bravada, the security light may come on and prevent the vehicle from starting due to issues with the vehicle's anti-theft system. This can occur if the ignition key is not recognized, often due to a malfunction in the key's transponder or the ignition system itself. Additionally, a drained battery or faulty wiring within the security system could also trigger the light. To resolve this, you may need to reset the system or have the key and ignition checked by a professional.