Principles of Operation

WARNING: This page is about a different car, the 2004 Lincoln Navigator and 2004 Ford Expedition. However, it is still accessible from the selected car via links, so may be relevant.

VEHICLE SECURITY MODULE

The vehicle security module receives inputs from the following:

Door ajar switches
Keyless entry keypad
Ignition switch
Remote keyless entry transmitter

The vehicle security module uses these inputs to control an output signal to the instrument cluster which controls the battery saver relay and courtesy lamp output.

INTERIOR LIGHTING SYSTEMS

The instrument cluster grounds the battery saver relay and supplies the power for courtesy lamps when any door ajar switch is opened, or the interior lamp (headlamp) switch is closed. The instrument cluster then supplies voltage to the interior lamp circuit. Vehicle speed must be less than 24 kph (15 mph) for the instrument cluster module to keep courtesy lamps on. The interior lamps will remain illuminated for up to 25 seconds after all doors are closed unless the instrument cluster module receives an input from any of the following:

Voltage from the ignition switch
A vehicle speed signal
Input from the keyless entry keypad through the vehicle security module
Input from the remote keyless entry transmitter lock or panic switch through the vehicle security module

ILLUMINATED ENTRY

Illuminated entry is activated when a vehicle is unlocked using the keyless entry keypad or the remote keyless entry transmitter. The vehicle security module then requests that the instrument cluster module supply voltage to the interior lamps. Illuminated entry is deactivated when the vehicle security module receives a lock signal from the remote keyless entry transmitter. Illuminated entry will also be deactivated when the instrument cluster module receives a change in ignition switch pid status.

BATTERY SAVER

The battery saver is activated when the instrument cluster module is not receiving voltage input from the ignition switch (OFF position). The instrument cluster module will then provide ground to the battery saver relay coil. This activates for a period of 10 minutes with the interior lamp (headlamp) switch in the OFF position, or a maximum period of 30 minutes with the interior lamp (headlamp) switch in the ON position, or a door is ajar, provided that the instrument cluster module does not receive any other input signals within the time-out period. The activated battery saver relay switches voltage to the demand lamp circuit. After time-out, the instrument cluster module disconnects ground from the battery saver relay coil, disabling the demand lamp circuit.