I found this in my 97 X Ford CD
The ignition lock anti-theft switch (19A438) can detect when the ignition
key cylinder is broken or "slam pulled" during a theft. The ignition lock
anti-theft switch is always monitored by the remote anti-theft personality
(RAP) module. This allows the alarm system to be triggered in case the
ignition lock anti-theft switch detects tampering of the ignition key
cylinder (even in the event the alarm is inactive at the time).
Refer to «Section 501-14B» for more details on the keyless entry remote
The door open warning lamp switch (14018) communicates to the RAP module
through the generic electronic module (GEM). This input to the RAP will
cause the anti-theft alarm to be sounded if the anti-theft alarm was armed.
The door disarm switches are assembled into the LH, RH, and liftgate lock
cylinders. The door disarm switch must be triggered before the mechanical
lock unlocks. This is to prevent the anti-theft alarm from activating when
it should have been disarmed.
The RAP module controls the anti-theft system and is the brains of the
keyless entry system. The RAP module communicates with the GEM to request
that the interior lights be turned ON/OFF with use of the keyless entry
remote transmitter, and the GEM communicates to the RAP to inform when the
door is opened. Refer to «Section 418-00» for inter-module communication.
The RAP has three wire connectors attached to it:
l The antenna for the keyless entry remote transmitter.
l 26 circuit connector, C336.
l 22 circuit connector, C338.
In addition to the perimeter alarm that uses the door open warning lamp
switch and hood switch, the RAP module also uses the ignition lock
anti-theft switch and the autolock/relock feature to prevent theft of the
vehicle. For a full description of the autolock/relock system, refer to
The anti-theft LED is found on the instrument panel to the right of the
right hand turn signal indicator. The THEFT LED is illuminated during
prearming and flashes when armed or triggered.
Prearming and Arming the System
The system can be armed if:
l The ignition is OFF.
l The PANIC alarm is OFF.
l All doors are closed.
There are three ways to prearm the system:
l Press the LOCK button on the transmitter.
l Press the 7/8 and 9/0 buttons on the driver door keyless entry keypad to
lock all doors.
l Open a door, press the power door lock button, and close the door.
After 30 seconds, the system will be armed and the THEFT indicator in the
cluster will flash every two seconds.
Disarming an Untriggered System
An armed system will be disarmed with one of these valid actions:
1. Pressing the UNLOCK button on the transmitter.
2. Placing a key in the door and turning to UNLOCK.
3. Turning the key to RUN or ACCY.
4. Entering the five-digit unlock code on the keyless entry keypad.
Triggering Anti-Theft Alarm
The anti-theft alarm can be triggered by the following conditions:
l The ignition cylinder is damaged with or without the RAP being armed.
l A door is opened without disarming the armed RAP module.
l Opening the hood (if the hood was open when the system was armed, it must
be closed before it can trigger the alarm).
The remote transmitter can activate a panic alarm which is similar to an
anti-theft alarm, but does not deactivate the starter or cause the THEFT
indicator to flash.
Disarming a Triggered System
If the system has been triggered (the horn honks and the lights flash), the
system can be disarmed by:
1. Pressing the UNLOCK or PANIC button on the transmitter.
2. Putting a key in the door and unlocking the door.
3. Turning the ignition to RUN/ACCY (turning the key to RUN/ACCY will not
disarm an alarm that has been triggered by the ignition lock anti-theft
4. Unlocking the doors by entering the unlock code on the keyless entry
"Cuda69" <email@example.com> wrote in message
>I have the factory installed anti-theft with keychain 'ARM/DISARM'
> When I bought the truck, it only worked the door locks which was great.
> Once I put a new battery in it, the ignition disable became functional
> again. It's a royal pain in the butt. EVERYTIME you go to start the
> truck, you have to have the key out and hit DISARM, even if you only
> stop for a second.
> Does anyone know how to activate and de-activate this feature?