Keyless entry is on its last legs. I have to punch unlock several times and aim the remote from different angles until it opens. I assume the battery is dying. Do you know if I can purchase a replacement battery or where to get a duplicate remote?

Hello Cathy

It does indeed have keyless entry. It needs reprogramming when you get a new remote. Also if you disconnect the battery. Usually a local car alarm fitting shop, or an auto-electrician will do it. Plus of course a Ford dealership.

https://www.google.com/search?q=Keyless+Entry+Remote+System+1999+Ford+Windstar

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Remote Transmitter Programming NOTE: All keyless entry remote transmitters must be programmed at the same time.
NOTE: Programming (or reprogramming) the keyless entry remote transmitters into the central security module can be accomplished using a diagnostic tool or by carrying out the following steps.

1. Turn the ignition switch from OFF to RUN eight times within 10 seconds, ending in RUN. If the module has successfully entered program mode, it will lock and then unlock all doors.

1. Within 20 seconds, press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed. Repeat this step for each transmitter.

1. If the door locks do not respond for any keyless entry remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Inspection and Verification.

1. Turn the ignition switch to the OFF position, or wait up to 20 seconds after Step 2, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the doors will lock and unlock one last time to confirm.

You did it like this ?
Programming -Keyless Entry Remote Transmitter NOTE: All keyless entry remote transmitters (15K601) must be programmed at the same time.
NOTE: All previous transmitter identification codes (TIC's) will be erased when programming mode is entered.
NOTE: To program (or reprogram) the keyless entry remote transmitters into the generic electronic module (GEM)(14B204), perform the following steps.

1. Turn the ignition from OFF to RUN eight times within 10 seconds, ending in RUN. If the GEM has successfully entered program mode, it will lock and unlock all the doors.

1. NOTE: The first TIC must be entered within 7.5 seconds of entering the program mode and additional TICs must be entered within 7.5 seconds of the first TIC. The programming mode is exited whenever the timing constraints are not met. Press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed.

1. If the door locks do not respond for any keyless entry remote transmitter, wait for several seconds and press the button again.

1. Turn the ignition switch to the OFF position, or wait up to five minutes after step 1, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the GEM will lock and unlock all the doors one last time.

The keyless entry system is controlled by the (GEM) - generic electronic module .
Keyless Entry The electronic door lock system has two main components:

• generic electronic module (GEM)(14B204)
• keyless entry remote transmitter (15K601)
• NOTE: Battery power and ground must be remove before disconnecting the GEM connectors to avoid setting false codes.
  Power Locks Operation The power locks feature allows the customer to lock and unlock the doors via momentary switches located on the driver and passenger door. When the GEM detects a momentary press of the driver or passenger lock button, the GEM will supply power to the driver or passenger lock actuators for approximately 250 ms from relays internal to the GEM. When the GEM detects a momentary press of the driver or passenger unlock button, the GEM will supply power to the driver or passenger unlock actuators for approximately 250 ms from relays internal to the GEM.
  Remote Keyless Entry Door Locks Operation The remote entry feature allows the customer to unlock the driver door, unlock all doors, and lock all doors using a valid remote transmitter as long as the ignition switch is not in RUN or START. The driver door is unlocked whenever the GEM detects a valid remote transmitter unlock transmission. All the doors are unlocked when the GEM detects a second valid remote transmitter unlock transmission within three seconds of the first transmission. All the doors are locked when the GEM detects a valid remote transmitter lock transmission. If the GEM detects a second valid remote transmitter lock transmission within three seconds of the first transmission, the doors will lock again, the horn will sound for 20 ms and the parking lamps will flash for 200 ms to indicate the doors are locked. If the GEM detects the driver or passenger door is ajar during the second lock transmission, the doors are locked again and the horn is sounded twice. If the GEM detects a valid remote transmitter lock transmission within three seconds of detecting a valid remote transmitter unlock transmission, the GEM will lock all the doors
• • The doors do not lock/unlock using the remote transmitter
  • Ignition switch.
  • GEM.
  • Remote transmitter.
  • Remote transmitter batteries.
  • GO to Pinpoint Test C .
  You followed the program instructions to the letter ? Programming -Keyless Entry Remote Transmitter NOTE: All keyless entry remote transmitters (15K601) must be programmed at the same time.
  NOTE: All previous transmitter identification codes (TIC's) will be erased when programming mode is entered.
  NOTE: To program (or reprogram) the keyless entry remote transmitters into the generic electronic module (GEM)(14B204), perform the following steps.
  
  1. Turn the ignition from OFF to RUN eight times within 10 seconds, ending in RUN. If the GEM has successfully entered program mode, it will lock and unlock all the doors.
  1. NOTE: The first TIC must be entered within 7.5 seconds of entering the program mode and additional TICs must be entered within 7.5 seconds of the first TIC. The programming mode is exited whenever the timing constraints are not met.
     Press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed.
  1. If the door locks do not respond for any keyless entry remote transmitter, wait for several seconds and press the button again.
  1. Turn the ignition switch to the OFF position, or wait up to five minutes after step 1, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the GEM will lock and unlock all the doors one last time.
  1. Take an have the vehicle checked for DTC'S

B1396 Power Door Lock Circuit Short to Battery GEM GO to Pinpoint Test B . B1397 Power Door Unlock Circuit Short to Battery GEM

Hi.

To program ( or reprogram ) a keyless entry remote transmitter into the remote keyless entry module, perform the following steps:

1. Turn the key to ON or ACC and short the two terminals of the program connector, a two-pin connector located below the driver's side of the instrument panel at the base of the steering column. All doors should lock and then unlock.
2. Press any button on each keyless entry remote transmitter in turn. All doors should lock and then unlock. If the door locks do not respond, press the button again (up to three times maximum with the same keyless entry remote transmitter). If the door locks still fail to respond, go to Pinpoint Test A.
3. Repeat Step 2 to program additional keyless entry remote transmitters into the remote keyless entry module (up to four keyless entry remote transmitters maximum).
4. Turn key off.
5. Remove the short from the program connector. All doors should lock and then unlock.
6. Verify that the keyless entry remote transmitters have been successfully programmed by pressing the LOCK or UNLOCK button on each one, and observing that the system responds by locking and/or unlocking the doors.


I hope this helps you.

Thanks!

Try reprogramming the remotes. Here are the instructions for the procedure. Hope it helps. Cobra!
Programming NOTE: All keyless entry remote transmitters (15K601) must be programmed at the same time.
NOTE: To program (or reprogram) the keyless entry remote transmitters into the RAP module, perform the following steps:

1. Make sure that the anti-theft system is not armed or triggered.

1. Turn the ignition switch (11572) from OFF to RUN eight times within ten seconds, ending in RUN. If the RAP module has successfully entered program mode, it will lock and then unlock all doors.

1. Within 20 seconds, press any button on a keyless entry remote transmitter, and the doors will lock and then unlock to confirm that each keyless entry remote transmitter has been programmed. Repeat this step for each transmitter.

1. If the door locks do not respond for any keyless entry remote transmitter, wait several seconds and press the button again. If the door locks still fail to respond, refer to Inspection and Verification.

1. Turn the ignition switch to the OFF position, or wait up to 20 seconds after step 2, to exit program mode. If a keyless entry remote transmitter has been programmed (or reprogrammed), the RAP module will lock and unlock all doors one last time to confirm.

Programming Electronic Door Lock Control System NOTE: The electronic door lock control processor (14B001) erases all previous keyless entry remote transmitter (15K601) from memory when the keyless entry remote transmitters are programmed or reprogrammed. The electronic door lock control processor can store up to four keyless entry remote transmitters in memory.

• To program (or reprogram) keyless entry remote transmitter into the electronic door lock control processor, perform the following steps:

1. Turn ignition switch to the RUN position and momentarily short the two terminals of the program connector taped to the wire assembly and located behind the glove compartment. All doors should lock and then unlock. Remove shorting pin.
   

1. Press any button on keyless entry remote transmitter. All doors should lock and then unlock to verify the keyless entry remote transmitter has been programmed. If door locks do not respond, press button again (up to three times maximum with the same keyless entry remote transmitter).
   

1. Repeat the above step to program additional keyless entry remote transmitters into the electronic door lock control processor (up to four keyless entry remote transmitters maximum).
   

1. Turn ignition switch OFF. All doors should lock and then unlock.
   

1. Check operation.
   

Programming a key fob is all about timing. You are most likely doing everything correctly, just not in the correct time sequence. Keep at it, it might take you a dozen times, but you can get it. A tip is to do it as quickly as possible.

Here are the programming instructions:

*** THERE ARE 2 POSSIBLE PROGRAMMING PROCEDURES. ***Procedure #1Note: Obtain all remote transmitters for this vehicle.
Note: Do not depress the brake pedal during procedure.

1. Turn ignition from OFF to RUN 8 times within 10 seconds, with the 8th time ending in RUN. Door locks will cycle to confirm programming mode. (Off is the position where you can remove your key, RUN is the position just shy of starting your car.)
2. Within 20 seconds press any button on the first keyless remote to be programmed. Door locks will cycle to confirm programming. If you only have one remote then skip to step 4.
3. Within 20 seconds, press any button on the second keyless remote. Door locks will cycle again to confirm programming. Repeat step 3. For all other remotes.
4. Turn ignition to OFF. Locks will again cycle to indicate end of programming mode.
   
   Procedure #2Note: Obtain all remote transmitters for this vehicle.
5. Fasten seat belts and close all doors.
6. Turn ignition from OFF to RUN 4 times within 6 seconds, with the 4th time ending in RUN. (Off is the position where you can remove your key, RUN is the position just shy of starting your car.)
7. Turn ignition to OFF. Acoustic signal will sound and system warning lamp will illuminate to confirm programming mode.
8. Within 10 seconds, press and hold any button on the first keyless remote. Wait for acoustic sound and warning lamp to flash (confirming programming) then release button on remote. Wait 2 seconds but within 10 seconds repeat step 4. For all other remotes. If you only have one remote then continue to step 5.
9. Turn ignition to Crank or wait 10 seconds to end programming mode.

Bonus Tip: You can save time and money purchasing a Ford Explorer Key Fob online from Keyless Entry Remote Inc.

try to reprogram the remotes using these instructions..........
i assume for 02 explorer not th 05 frestyle listed (although similar procedure)
Remote Transmitter Programming NOTE: All remote transmitters are programmable and must be set at the same time.

1. Make sure that the anti-theft system is not armed or triggered and key code programming is not active.

1. Open the door, then press the driver door lock control switch UNLOCK button.

1. 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.

1. 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.

1. 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.

1. 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.

I assume you are talking about the key fob. First, pry it open and change the battery. Watch which way the + goes.
If your key fob works, and the battery did not fix it, try reprogramming following the instrcutions in the owner manual. May need both fobs present at the same time.
Note; This is different than programming the anti-theft key.