Interior Lighting Systems Description and Operation

Interior Lighting Systems Description and Operation

Interior Lighting

The interior lighting consist of lamps that may not be dimmed (Interior Lamps) and lamps that may be dimmed (Interior Lamps Dimming).

Interior Lamps

The first group of lamps are the interior courtesy lamps that may not be dimmed manually, these include:

* The dome lamp
* The instrument panel (I/P) compartment lamp
* The I/P courtesy lamps
* The overhead console courtesy lamps
* The rear compartment lamp
* The roof rail courtesy/reading lamps
* The sunshade vanity mirror lamps

Interior Lamps Features

The interior lamps system features the following functions:

* An illuminated entry feature that illuminates the courtesy lamps when entering the vehicle or activating the remote keyless entry system.
* An illuminated exit feature that illuminates the courtesy lamps when the ignition key has been removed from the ignition.
* An inadvertent power feature that supplies voltage to all interior lamps after the ignition is turned OFF. The inadvertent power feature will deactivate all interior lamps after 20 minutes to prevent battery rundown.
* A theatre dimming feature that will slowly dim the interior lamps from full brightness to off.
* An I/P dimmer switch that illuminates the courtesy lamps.
* Individual switches for control of each interior lamp that is not illuminate with the interior lamp switch.

Courtesy/Illuminated Entry Lamps

When the body control module (BCM) is in an active state (awake) it energizes the courtesy lamps supply voltage circuit. The courtesy lamps supply voltage circuit supplies voltage to all of the interior lamps, including the illuminated entry lamps (courtesy lamps). The illuminated entry lamps are turned on when they receive a battery positive voltage from the courtesy lamp supply voltage circuit of the BCM. When the ignition is in the LOCK position the BCM will apply the courtesy lamp supply voltage circuit under the following conditions:

* The door jamb input transitions to an active state (opening a door).
* The use of the remote keyless entry (RKE) to unlock the side doors.

When the courtesy lamps supply voltage circuit and the courtesy lamp low control circuit are active the courtesy/illuminated entry lamps will illuminate. The courtesy lamps/illuminated entry lamps include the following interior lamps:

* The dome lamp
* The roof rail courtesy lamps
* The I/P courtesy lamps
* The overhead console courtesy lamps

When the driver uses the remote function actuator transmitter to unlock the doors, the BCM will illuminate the courtesy lamps for approximately 40 seconds, unless another BCM function causes the lamps to remain active. If the ignition switch is turned to either the RUN or START position the courtesy lamps will turn off immediately.

When the door latch switch signal circuit is active with the ignition in the OFF position the BCM will illuminate the courtesy lamps. The courtesy lamps will remain illuminated for approximately 25 seconds, after the door latch switch signal circuit becomes inactive, unless another BCM function causes the lamps to remain active. If the ignition switch is turned to either the RUN or START position the courtesy lamps will turn off immediately.

Courtesy/Illuminated Exit

The illuminated exit feature will activate the courtesy lamps when the key IN input of the BCM transitions from an active state to an inactive state (removing the ignition key). When the key is removed from the ignition, the key IN input to the BCM becomes inactive. The BCM will illuminate the courtesy lamps for approximately 25 seconds, unless another BCM function causes the lamps to remain active.

Inadvertent Power Feature

Inadvertent power feature provides a similar function for the interior lamps as a retained accessory power feature. The BCM will energize the courtesy lamps supply voltage circuit when the BCM is in the active state (awake). When the courtesy lamps supply voltage circuit is energized, it supplies voltage to all the interior lights. The BCM will continue to supply voltage to the interior lamps after the ignition is turned OFF so that the interior lamps may be operated.

The inadvertent power feature will also act as battery run down protection by deactivate the courtesy lamps supply voltage circuit after 20 minutes once the BCM becomes inactive (ignition OFF and no BCM input activity.)

Theater Dimming

The theatre dimming feature that will slowly dim the interior lamps from full brightness to off. The following actions will over ride the theatre dimming feature causing the courtesy lamps to deactivate immediately if no other BCM function commands the courtesy lamps on:

* A transition from active to inactive of the interior lamps switch (turning off the interior lamps switch).
* A LOCK command from the remote keyless entry system.
* A last door closed locking function (locking and closing all the doors).

Courtesy Lamps Manual Operation

The courtesy lamps, may be manually operated by the IP dimmer switch. When the I/P dimmer switch is placed in the DOME position the BCM receives a ground from the courtesy lamp switch signal circuit. Upon receiving the courtesy lamp switch signal the BCM then applies battery positive voltage to the courtesy lamp supply voltage circuit, which illuminates the courtesy lamps. The voltage for all interior lamps is supplied by the courtesy lamp supply voltage circuit of the BCM, whenever the BCM is active. The interior lamp switch will override any BCM operation of the interior lamps, such as entry illumination.

Dome Lamp

The dome lamp is turned ON by the I/P dimmer switch or during illuminated entry.

During illuminated entry or when the I/P dimmer switch is DOME the BCM wakes up and then energizes the courtesy lamps supply voltage circuit, suppling voltage to all interior lamps.

I/P Compartment Lamp

When the I/P compartment is opened the I/P compartment lamp illuminates, if the courtesy lamps supply voltage circuit of the BCM is activated (BCM awake).

The I/P compartment lamp illuminates when the courtesy lamps supply circuit of the BCM supplies voltage to the IP compartment lamp and the IP compartment switch closes, providing a ground path.

I/P Courtesy Lamp

The I/P courtesy lamp is turned ON by the IP dimmer switch or during illuminated entry.

During illuminated entry or when the I/P dimmer switch is DOME the BCM wakes up and then energizes the courtesy lamps supply voltage circuit, suppling voltage to all interior lamps.

Overhead Console Courtesy/Reading Lamp

The overhead console courtesy lamp is turned ON by the I/P dimmer switch, the overhead console reading lamp switch, or during illuminated entry.

Rear Compartment Lamp

When the rear compartment is opened, the rear compartment lamp illuminates.

When the rear compartment is opened, the rear compartment courtesy lamp switch sends a ground signal to the BCM, waking the BCM. When the BCM wakes up it will then energize the courtesy lamps supply voltage circuit , suppling voltage to the rear compartment courtesy lamp. The rear compartment courtesy lamp switch will provide a ground path for the rear compartment courtesy lamp in order to illuminate the lamp.

Roof Rail Courtesy/Reading Lamps

The roof rail courtesy lamps are turned ON by the I/P dimmer switch, the individual roof rail courtesy lamp switch, or during illuminated entry.

During illuminated entry or when the I/P dimmer switch is ON the BCM wakes up and then energizes the courtesy lamps supply voltage circuit, suppling voltage to all interior lamps.

The roof rail courtesy/reading lamps can be turned on from the individual roof rail courtesy lamp switch. The BCM supplies voltage through the courtesy lamps supply voltage circuit when the BCM is awake. Manually turning on the roof rail courtesy lamp switch provides a ground path.

Sunshade Vanity Mirror Lamps

When the vanity mirror cover on the sunshade is opened, the sunshade mirror lamp illuminates.

The sunshade mirror lamps receive voltage from the courtesy lamps supply voltage circuit anytime the BCM is awake. The sunshade illuminated mirror lamps receive ground from their individual switches when the sunshade is open.

Interior Lamps Dimming

The second group of lamps include lamps which may be dimmed. This group uses a combination of class 2 dimming and incandescent lamps:

* PRNDL lamp
* Head-up display (HUD) switch
* Door switches and window switches
* HVAC control head assembly
* Outside rear view mirror switches
* Driver information center (DIC)
* Radio
* Steering wheel controls
* The instrument panel cluster (IPC)
* Traction control switch

When the headlamp switch is placed in the PARK position, ground is supplied through the headlamp switch to body control module (BCM). The BCM also applies a voltage reference and a low reference signal to the interior lamp switch. When the interior lamp switch is varied, the position of the switch is applied through the I/P dimming control circuit to the BCM. The BCM then applies a voltage to the interior lamps.

Incandescent Dimming

The incandescent lamps become illuminated when the park lamps are ON. The brightness of all the incandescent lamps is determined by a variable voltage signal from the dimmer switch and sent through the instrument panel (I/P) lamp supply voltage circuit. The incandescent lamps are located in various components, refer to Interior Lights Dimming Schematics (Interior Lights Dimming Schematics).

Class 2 Dimming

The class 2 lamps will be at full brightness when the ignition is on and the park lamps are OFF. When the park lamps are turned on, the BCM applies a signal to the class 2 circuit to the IPC and DIC. The class 2 display will then dim to the level set by the dimmer switch. The brightness of all the class 2 displays is determined by a variable voltage signal produced by the dimmer switch. With the park lamps activated, the IPC and DIC will dim for night time viewing.

Driver Controls and Modules

The BCM module processes the inputs and the controls. The ambient light sensor supplies the BCM with a signal for daytime conditions or for low light conditions:

* The body control module (BCM)
* The driver information center (DIC)
* The instrument panel cluster (IPC)

Driver controls include the following components:

* The I/P dimmer switch
* The door jamb switches
* The headlamp switch
* The rear compartment lid ajar switch
* The overhead console courtesy reading lamp switch
* The roof rail courtesy reading lamp switch
* The sunshade vanity mirror lamps switch
* The IP compartment lamp switch