98~2001 Ex 5.0 and 99~2000 Ranger V6 use exactly the same PATS setup. If they are from different vehicles, the PCM and PATS Module must be "introduced" to each other to work as a team. Then the PATS Module needs to be trained to be recognize the keys. Both steps require a dealer tool.
If the current setup won't work, then you could swap in your spare parts.
BTW, if all of the parts (PCM, PATS Module and keys) are installed from the same donor, then PATS should work without the dealer's help. The only problem with that approach is that the Ranger door keys won't match the Ex ignition keys. It MAY be possible to swap the door locks as well but I've never tried it between Ranger and Explorer.
