Short of disconnecting the battery system, there is no way to disable a vehicle anti–theft device from outside the vehicle. To be sure, there is a way to disable an anti-theft system. However, you have to know the point chosen by the owner. For obvious reasons, we won’t go into specifics other than to say that some owners choose one of the stalks as the override point for the system, while other owners will use a special press of the mirror button. Still, others use a switch that isn’t used often so that neither looks as if it were tampered with.
For more info, see What are the Most Effective Auto Anti Theft Devices