Do you have to reprogram anything after changing ignition switch on a 1999 mercury mystique?

Generally, when changing the ignition switch on a 1999 Mercury Mystique, you do not need to reprogram anything, as the ignition switch does not typically require programming. However, if the vehicle has an anti-theft system, you may need to reset or reprogram the system to recognize the new switch. It's always a good idea to consult the vehicle's service manual or a professional mechanic for specific instructions based on any additional features your vehicle may have.