Ford Mercury Villager 1997 Owner's Manual page 119

Remove the two batteries by snapping open the lid of the remote
transmitter. The transmitter can be snapped apart by twisting
a thin coin between the two halves of the transmitter. Replace the
batteries with new ones as shown in the above illustration.
Close the lid securely. Press both the LOCK and the UNLOCK
button two or three times to test the remote transmitter operation.
If the batteries are removed for any reason other than
replacement, repeat the steps in Replacing the batteries to test your
remote transmitter(s).
An improperly disposed battery can hurt the environment.
Always confirm local regulations for battery disposal.
The remote transmitter is waterproof; however, if it does get
wet, immediately wipe it completely dry.
The operational range of the remote transmitter extends to
approximately 49 feet (15 meters) from the vehicle. This
range may vary with conditions.
THIS DEVICE COMPLIES WITH PART 15 OF THE FCC
RULES. OPERATION IS SUBJECT TO THE FOLLOWING TWO
CONDITIONS: (1) THIS DEVICE MAY NOT CAUSE
HARMFUL INTERFERENCE, AND (2) THIS DEVICE MUST
ACCEPT ANY INTERFERENCE RECEIVED, INCLUDING
INTERFERENCE THAT MAY CAUSE UNDESIRED
OPERATION.
Replacement/Additional Transmitters
In the event a transmitter is lost or an additional remote
transmitter needs to be set, you must change the ID code. Follow
the steps below to change the ID code of your system, or
return the remaining transmitter(s) to your dealer for
reprogramming of your remote entry system. This is necessary to
prevent unauthorized use of the lost transmitter.
Controls and Features
115