How do you disable the factory anti theft on a Ford Mustang?

You can't disable the factory anti-theft system on a Ford Mustang (or any modern car) without the proper key or access codes. Attempting to bypass or disable it through any other means is illegal and likely to damage your car's electrical system. The anti-theft system is integrated deeply into the vehicle's computer systems and isn't something you can easily circumvent.

If you've lost your keys, your best course of action is:

* Contact a locksmith specializing in automotive security: They have specialized equipment and knowledge to program new keys and potentially reset the system if necessary. They'll need proof of ownership.

* Contact a Ford dealership: They can replace keys and reprogram the system, but this will be the most expensive option. Again, proof of ownership will be required.

Any attempt to bypass the anti-theft system yourself risks serious damage to your vehicle and could even void any existing warranty. It's far safer and more reliable to utilize the legitimate methods described above.