Lost keys alarm is now going off.

First thing you need to do is make sure that it is not stolen. Then you need to take it to a dealer to have it reflashed to recognize the new anti-theft device.

you wont,, you will have to replace the ignition switch /tumbler to get the alarm back working.

You have to remove the plastic cover on the bottom of the ignition column.Where the tumbler goes in you will see a shiny pin that hold the tumbler tooth column.you can drill that pin out carefully and use patience starting with a small bit size and working your way up.don not remove any aluminum material from the column as your new tumbler will not lock in to the column. These cars and columns are plentiful in the junkyard if you are not successful and don't take a lot of time to swap out.

Usually a sign the tumblers in the lock cylinder have worn out or jammed.
You may have to get the lock cylinder drilled out and replaced.

You can probably go to a junkyard, and steal the tumbler out of another cars ignition, just make sure that you have the set of keys to go with it. As well, if your ignition key is for your locks as well, make sure that you take those tumblers out of the door because you'll need those as well.

look at the steering column below the ign lock and tumbler there should be a small hole turn key to on pos and push a small rod up the holethis then should release the lock and tumbler,no hole then wheel and coumn has to be stripped to get to lock retainer

Are you aware? you have the key and tumbler and another part under the dash on the steering column called the ingition switch.
They both have to be aligned in sync to operate properly.
Question? is this a tilt steering wheel,if it is and you dont know anything about it I suggest you get a professionel to do this kind of job.
You really have to know what your doing for this one.

you need to have the keys programmed with a ford scantool. that's the only way.

might be ignition tumbler , my friend had same problem , the key sensor broke , there is reset process after new tumbler is installed

pull cover off of bottom and turn key to on and push pin up with scratch owl should be able to remove tumbler then