Lost ignition key to 2003 Ford Explorer

Your best option is to call the dealership that originally sold the vehicle when it was new. They keep the key codes on file, but I'm not sure for how many years. The people in the parts department can also get the key code from Ford, then they can make you a new key. If you had an electronic key, they should be able to get that too and program it for you, but Ford has a history of not making parts available for their cars one they're three to five years old. In that case contact a locksmith. They can get the doors open, and they have keys and other solutions available that dealers don't get involved with.

If you have to go to a dealer other than the selling dealer, take the vehicle's ID number. That SHOULD be all they need. For a lot of other parts, especially on Ford products, they need to know the date of production because Ford makes a lot of changes in the middle of model years. The problem is unless you know the production date, you have to get the driver's door open so you can look on the sticker.

Ten years is more than most dealers go back. The one I worked for saved records for seven years, but that was a Chrysler dealership. Chrysler used to have records that went back to the 1940s or 50s, but I don't know if that is still the case. Regardless, it seems to me they should be able to get help right from Ford, otherwise you're stuck with the locksmith. In the long run that might be a better alternative. The police used to open locked doors for people but most of them stopped doing that because too many latch assemblies were getting broken, then the owners complained and threatened to sue.