Keyless Entry
WARNING: This page is about a different car, the 2002 Ford Ranger. However, it is still accessible from the selected car via links, so may be relevant.
The keyless entry remote transmitter sends a frequency that is received by the central security module internal antenna. Depending on the frequency received, the central security module will lock all doors or unlock the driver door. If the unlock frequency is received again within five seconds of the first unlock, the central security module will unlock all doors.
If the frequency received is from the panic button, the central security module will cycle ground to the parking lamps and horn. The parking lamps and horn will continue to cycle until the panic button is pressed again or the ignition switch is turned to the RUN position.