Ford 2003 Explorer Owner's Manual page 62

Locks and Security
To deactivate/reactivate the autolock feature using the ignition
lock cylinder and interior power door locks control
1. Close all the doors.
2. Ensure that the ignition lock cylinder is in the OFF position.
3. Note: Steps 4 through 8 must be carried out within 30 seconds. Turn
the ignition lock cylinder from OFF to RUN.
4. Press the power door locks UNLOCK control three times.
5. Turn the ignition lock cylinder from RUN to OFF.
6. Press the power door locks UNLOCK control three times.
7. Turn the ignition lock cylinder from OFF to RUN.
8. Ensure that the vehicle's horn chirps. This chirp indicates that the
feature is in an enable/disable mode and ready to accept program
changes.
9. Press the power door locks UNLOCK control once, then the LOCK
control once, in order to toggle the autolock feature.
10. Ensure that the horn chirps once; there should only be one horn
chirp, indicating that the autolock feature has been deactivated. If one
chirp is heard, followed by a longer sound of the horn, the autolock
feature has been reactivated.
11. Turn the ignition lock cylinder to the OFF position, or wait two
minutes, in order to exit the enable/disable mode.
12. Exit the vehicle and ensure that the horn chirps once to indicate that
a feature has been changed and that the autolock feature has been
toggled.
SECURILOCK PASSIVE ANTI-THEFT SYSTEM
SecuriLock passive anti-theft system is an engine immobilization
system. This system is designed to prevent the engine from being started
unless a coded key programmed to your vehicle is used. The use of
the wrong type of coded key may lead to a "no-start" condition.
Your vehicle comes with two coded keys; additional coded keys may be
purchased from your dealer. The dealer can program your spare keys to
your vehicle or you can program the keys yourself. Refer to
Programming spare keys for instructions on how to program the coded
key.
Note: The SecuriLock passive anti-theft system is not compatible with
non-Ford aftermarket remote start systems. Use of these systems may
result in vehicle starting problems and a loss of security protection.
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