Principles of Operation

Interior Lighting

Principles of Operation

The Body Control Module (BCM) controls all the interior lighting functions and timing by monitoring inputs from the following:

- door ajar switches

- ignition state

- instrument panel dimmer switch (monitored by the Steering Column Control Module (SCCM) )

- Remote Keyless Entry (RKE) system

- vehicle speed

The BCM (Body Control Module) turns off the courtesy lamps when the vehicle speed exceeds 15 km/h (9 mph) or 5 km/h (3 mph) for the puddle lamps, unless the courtesy lamps are turned on using the instrument panel dimmer switch.

Interior Lamp Arbitrator

The interior lamp arbitrator (programming within the BCM (Body Control Module) ) chooses between the interior lighting delay, the illuminated entry and exit, the battery saver, and the alarm flash processing to determine which feature has precedence of activating and deactivating the interior lamps.

Ambient Lighting

The Interior Lighting Control Module (ILCM) provides voltage and ground to the LEDs. There are 3 different color LEDs (red, blue and green) housed within each LED assembly. By illuminating various color combinations, the LEDs can produce 7 different colors of ambient light. The ambient lighting select switch and ambient lighting dimmer switch are inputs to the ILCM (Interior Lighting Control Module). With each press of the ambient lighting select switch, the ILCM (Interior Lighting Control Module) cycles through a different color variation or turns the ambient lighting feature off. With each press of the ambient lighting dimmer switch, the ILCM (Interior Lighting Control Module) changes the brightness setting of the ambient lighting. The module retains the last color and brightness setting between uses.

The ILCM (Interior Lighting Control Module) also receives messages regarding courtesy lamp door ajar status, illuminated entry status, accessory delay status, courtesy lamp delay status, battery saver relay status and ignition status over the network from the BCM (Body Control Module). The ILCM (Interior Lighting Control Module) uses these inputs to determine when the ambient lighting is turned on to the preset color and brightness setting or to customer-selected color and brightness setting. The color and brightness setting can only be changed when the ignition is in RUN or ACC, the parking lamps are on and all of the doors are closed.

Field-Effect Transistor (FET) Protection

A Field-Effect Transistor (FET) is a type of transistor that, when used with module software, monitors and controls current flow on module outputs. The FET (Field-Effect Transistor) protection strategy prevents module damage in the event of excessive current flow. For additional information, refer to Principles of Operation in Body Control Systems.

The BCM (Body Control Module) FET (Field-Effect Transistor) protected output circuits for the interior lighting system are the interior courtesy lamp and puddle lamp output circuits.