1998 Ford Windstar GL minivan

I had the exact same problem

get a small screwdriver and put the key in the run position, insert the screwdriver in the little hole below the ignition and push up on the little button inside then pull on the ignition and it will slide out. clean all the contact surfaces with contact cleaner like alcohol (do not use harsh chemicals or oil of anykind). use 800 grit sandpaper if you have to. once all contact areas have been cleaned (including the 2 feeler like contacts) reassemble the ignition by pushing it back in... the issue should be resolved, if not, repeat :).

the key buzzer switch in the ignition is bad .It is part of the ignition switch.