try to reprogram the remotes using these instructions..........
i assume for 02 explorer not th 05 frestyle listed (although similar procedure)
Remote Transmitter Programming
All remote transmitters are programmable and must be set at the same time.
- Make sure that the anti-theft system is not armed or triggered and key code programming is not active.
- Open the door, then press the driver door lock control switch UNLOCK button.
- Turn the key from OFF to ON 8 times within 10 seconds, with the eighth turn ending in ON. If the program mode is sucessfully entered the doors will lock and unlock to confirm.
- Press any button on a remote transmitter, and the doors will lock and then unlock all doors to confirm that the remote transmitter is programmed. All remote transmitters must be programmed within 20 seconds of each other. Up to four remote transmitters can be programmed to the vehicles security module each time programming mode is entered.
- If the door locks do not respond for any remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Locks, Latches and Entry Systems — Late Build or Locks, Latches and Entry Systems — Early Build in this section.
NOTE: Exiting is acknowledged by locking and unlocking the doors if at least one remote transmitter has been programmed.
Exiting the programming mode is accomplished if one of the following has occurred:
- The key transitions to OFF.
- 20 seconds have passed since entering programming mode or since the last remote transmitter was programmed.
- Four remote transmitters have been programmed.