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

The first group listed below includes lamps that may not be dimmed

Interior Lamps Features

The interior lamps system features the following functions:

Courtesy Lamps

When either one of the front doors is opened, ground is applied through the door latch door open switch and the door open switch signal circuit to the door module indicting the door open position. In response to this signal, the door module sends a GMLAN serial data message to the BCM of the door open position. Or, when either one of the rear doors is opened, ground is applied through the door latch door open switch and the rear door open switch signal circuit to the BCM is indicating the rear door open position. Once a door open message or signal received, the BCM will then apply battery voltage from the CTSY/RF TRN fuse through the courtesy lamp supply voltage circuits illuminating the lamps listed below:

Courtesy Lamps Manual Operation

The courtesy lamps can be manually turned ON by the IP dimmer switch. When the dimmer switch is placed in the DOME position, ground from G304 is applied through the dimmer switch and the courtesy lamp switch ON signal circuit to the BCM indicating the courtesy lamps ON request. In response to this signal, the BCM then applies battery positive voltage from the CTSY/RF TRN fuse through the courtesy lamp supply voltage circuit illuminating the courtesy lamps listed above. The courtesy lamps ON operation of the dimmer switch will override any BCM operation of the interior lamps already in progress.

Keyless Entry Interior Illumination

When the remote function actuator transmitter is used to unlock the doors, the BCM receives a door-unlock signal. The BCM must have inputs that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF, and all the doors are closed. The BCM will then illuminate the courtesy lamps and will remain illuminated for approximately 25 seconds after the door is closed. If the door locks are activated to the LOCK position, or if the ignition switch is turned to either the RUN or START position, the BCM will turn OFF the courtesy lamps 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.

Theater Dimming

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

I/P Compartment Lamp

The BCM supplies battery positive voltage from the INT LAMPS fuse through the inadvertent power courtesy lamps circuit to the IP compartment lamp. When the IP compartment is opened, the IP compartment lamp switch closes to ground and the lamp illuminates.

Rear Compartment Lamp

The BCM supplies battery positive voltage from the INT LAMPS fuse at all times through the inadvertent power courtesy lamps circuit to the rear compartment lamp. When the rear compartment is opened, the rear compartment lamp switch closes to ground and the lamp illuminates.

Overhead Console Lamp and Roof Rail Courtesy/Reading Lamps

The courtesy/reading lamp is a duel purpose lamp that can be illuminated two different ways. First, the lamp can be turned ON during courtesy lamp operation as described above. Second, the lamps can be turned ON individually for reading lamp operation by the lamp switch. The BCM supplies battery voltage from the INT LAMPS fuse through the inadvertent power courtesy lamps circuit to the courtesy/reading lamps for reading lamp operation only. Ground for the courtesy lamp module or the roof/rail reading lamps is provided at G402

Sunshade Vanity Mirror Lamps

The BCM supplies battery voltage from the INT LAMPS fuse through inadvertent power courtesy lamps circuit to the vanity mirror lamps. When the vanity mirror cover on the sunshade is opened, the vanity mirror lamp switch is closed to ground and the lamp illuminates. Ground for the vanity mirror lamps is provided at G402.

The second interior lighting group includes lamps which may be dimmed. This group may use a combination of vacuum fluorescent (VF) illumination, LED illumination and incandescent lamps.

When the ignition switch is turned to the RUN position, the instrument panel cluster (IPC), radio VF display, and the HVAC control assembly turns ON at maximum brightness. When the headlamp switch is in the PARK or HEADLAMP ON position, all incandescent and LED back lighting turn ON at the dimming level indicated by the instrument panel (I/P) dimmer switch. The dimmer switch is used to increase and decrease the brightness of the interior backlighting components. The BCM supplies a voltage reference through the I/P dimming voltage reference circuit to the interior lamp dimmer switch, which is part of the headlamp switch. When the dimmer switch is placed in a desired brightness position, reference voltage is applied through the dimmer switch rheostat and the I/P lamps dimmer switch signal circuit to the BCM. The BCM interprets this voltage signal, then applies a pulse width modulated (PWM) voltage through the I/P lamps supply voltage circuit and the LED dimming supply circuit to all related interior lamps, illuminating them to the desired level of brightness. At the same time the BCM also sends a GMLAN serial data message to the driver door module (DDM) and the front passenger door module (FPDM) indicating the back lighting request with the desired level of brightness. The door modules then illuminate the door switches and the heated/cooled seat switch back lighting to the requested intensity.

The BCM controls the lighting system through circuits that enable the exterior lamp functions of the park lamps, the head lamps, the fog lamps, and the interior lamps. The BCM opens these enabling circuits 10 minutes after the ignition switch is turned OFF with no lamp switch activity. If the ignition switch is turned to any position other than OFF, or if a lamp switch is activated during this time period, the timer resets for another 10 minutes.