Take something to prove you own the car to the manufacturer and they can send someone to have a new key fitted.
Locksmith
If keys are lost to a vehicle call someone to bring a spare if possible. If not then call a locksmith to have them replaced.
If you don't have the code, you will have to replace the lock cyl. They pop out if you know the procedure (and come with keys).
Keys of the Kingdom was created on 1991-06-25.
Defective ignition switch.
When my father in law lost his master key for his vehicle (his vehicle came with 2 keys, and it has a chip in it so he couldn't make duplicates) He had to go to the dealership and pay like 250.00 for a new one.
It sounds like your cars computer forgot what keys are supposed to start the car. In order to get the keys back into the cars computer, you need to either have the car towed to a dealer, or have a trained and equipped lock smith come to the car, this is not a do it yourself type job as it requires a proprietary computer system and connector. The second generation Passive Anti-Theft-System (PATS) found in this year Cougar requires dealer reprogramming if you have less than two working keys. I recommend making sure that you have at least 3 programmed keys to the car, this way if you lose one, you can still program your own key.
The Italian and Egyptian campaigns.
The cast of Mystery of the Keys - 1991 includes: Joe Abdo as Tourist Richard Dysart Nina Franoszek as Becky Lotti Huber Peter Mark Richman
It should be located under the dashboard. usually behind the center console (heater controls, stereo etc...) You should be able to just pull out the wire that is fitted into it. But be careful. The same chime is used to let you know if you've left your headlights on, or your keys in the ignition.
The #1 cause of hard starting a 1991 ford explorer is having lost your keys
Get the VIN number, also your proof of ownership.Then go to a Mercury dealership, give them ur info and $40 at the least for new keys.