Principles of Operation

PRINCIPLES OF OPERATION

The interior lighting can be separated into two distinct modes of operation: the interior lighting and the demand lighting. The lighting control module (LCM) controls all of the interior lighting in the vehicle, as described in the following text.

The front dome lamps, rear reading lamps and instrument panel interior lamps can be illuminated either by opening any of the vehicle doors (interior lamp function) or by moving the dimmer switch to the dome lamp position (demand lamp function).

When any door is open, the door ajar switch grounds an input to the LCM which then sends power to the interior lamps. The voltage sent to the interior lamps gradually increases from 0 volts to 12 volts within 500 ms (±50 ms), to achieve the theater lighting effect. When the door is closed, the door ajar switch breaks the ground to the LCM input which then gradually reduces the power from 12 volts to 0 volts within 5 seconds (±.5 second).

When the dimmer switch is moved to the dome lamp position, it grounds an input to the LCM which in turn sends 12 volts to the front dome lamps, rear reading lamps and instrument panel interior lamps. When the dimmer switch is moved away from the dome lamp position, it breaks the ground to the LCM input which then ceases to send power to the front dome lamps, rear reading lamps and instrument panel interior lamps.

The front map lamps, rear reading lamps, glove compartment lamp, vanity mirror lamp, luggage compartment lamp (and engine compartment lamp police and natural gas vehicles only) are provided with power by the LCM demand lighting output, and are illuminated when a dedicated switch closes, completing the ground circuit for the appropriate lamp(s). As the LCM provides constant power to the demand lamps, there is no ramp up or ramp down time. The illumination is instantaneous once the appropriate switch is closed.

When a door handle is lifted, or a keypad button is pressed, it grounds an input to the LCM which then illuminates the interior lighting using the theater lighting feature. When the unlock button on a remote keyless entry transmitter is pressed, the DDM sends a pulse signal to the LCM which then illuminates the interior lighting using the theater lighting feature. In either instance the interior lamps will extinguish after the time-out using the theater lighting feature. If a lock button on the remote keyless entry transmitter is pressed, or the ignition is turned to the RUN or ACC position, it will extinguish the interior lamps prior to the end of the time-out.

The battery saver will disrupt power to the interior lamps after 10 minutes, the demand lamps after 30 minutes, and the headlamps after 10 minutes. Turning the ignition switch to the RUN or ACC position will terminate the battery saver feature by disabling the interrupt timers and reinstate power to the lamps.

A reset event will set the interior lamps interrupt timer to zero. The reset events for the interior lamps interrupt timer are: turning on the interior lamps by using the dome lamp switch or opening any door (as detected by the door ajar switches).

A reset event will set the demand lamps interrupt timer to zero. The reset events for the demand lamps interrupt timer are: opening the luggage compartment door or opening any door (as detected by the door ajar switches).

When the panic button on a keyless entry remote transmitter is pressed, the panic alarm will override the interior lamps and headlamps battery saver functions for the duration of the alarm.

On police vehicles only, the dark car feature is a special order option that offers deletion of the illuminated entry function. Upon vehicle power-up, the LCM will monitor the dark car input signal for a ground condition of longer than two seconds. If the ground is present, no interior lighting will be provided during entry or exit of the vehicle. The interior lighting will, however, still operate on demand whenever the dome lamp switch is active. A ground will be provided to the LCM by an on-line connector within the unique police 14401 instrument panel harness. The male terminal side connector will be retained on a portable clip and the female terminal connector will be tear-taped to a bundle. If the dark car feature is necessary, the connection will be made on the assembly line. If no connection is made, the default state of the LCM will be to provide illuminated entry. The vehicle can be reconfigured by removing the power to the module, changing the dark car input from (or to) a ground or an open circuit, and then reapplying power to the module. The vehicle can also be reconfigured by changing the dark car input signal from (or to) a ground or an open circuit, entering diagnostics and then exiting diagnostics.