From http://www.powerstroke.org/forum/99-...de-update.html

On a pre-2002 you have one 20 minute option..
The De Bruijn sequence!! It's 3125 numbers that WILL unlock your door..
Once it's unlocked backtrack 5-10 numbers and start from there until you figure out
what 5 digits did it.. Not fun, but you can do it quicker then going to the dealer.

Here's the link to the number and info you need to do this!
http://everything2.com/index.pl?node_id=1520430