Interior Lamps

WARNING: This page is about a different car, the 2022 Cadillac CT4. However, it is still accessible from the selected car via links, so may be relevant.

The interior lighting system consist of two groups. This first group includes lamps that may not be dimmed.

Body Control Module
Cargo Lamp Switch
Dome Lamps
Dome Lamp Switch
Instrument Panel Compartment Lamp
Reading Lamps
Rear Compartment Courtesy Lamp
Sunshade Mirror Lamps

Dome Lamps

The dome lamps are controlled by two ways, the S36 Dimmer Switch and door ajar input to the K9 Body Control Module (BCM). When any door is opened, the door ajar switch contacts close and the BCM receives a door-open input. The BCM illuminates the dome lamp when any door is opened or a door lock/unlock request is activated with the key fob. After all doors have been closed, the dome lamp will remain illuminated approximately 3 seconds after the last door closes. In the event that the dome lamp were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the dome lamp control circuit to prevent total battery discharge. The dome lamps will turn OFF using the theater dimming feature when controlled by the BCM.

There are vehicles equipped with Dome ON/OFF switch and Dome Defeat switch. When Dome Defeat is ON, the dome lamp operation based on courtesy by BCM is disabled. Dome Defeat indicator will be ON to inform the customers that courtesy is disabled. There are vehicles equipped with Dome ON/OFF switch and Dome Defeat switch. When Dome Defeat is ON, the dome lamp operation based on courtesy by BCM is disabled. Dome Defeat indicator will be ON to inform the customers that courtesy is disabled.

To enable courtesy lamp operation by BCM, Dome Defeat should be OFF (Indicator will be OFF)

Keyless Entry Interior Illumination

When the operator uses the keyless entry transmitter in order to unlock the doors, the BCM receives a door-unlock signal. The BCM must receive inputs from various systems that indicate that the ignition switch is OFF, the courtesy lamp switch is OFF, and all doors are closed before the BCM will activate the interior lamps. After all doors have been closed, the courtesy lamps will turn OFF immediately if the ignition switch is turned to the ON position, the door locks are LOCKED via the keyless entry transmitter or the interior lock/unlock switch or the exterior door handle lock switch, or approximately 20 seconds after driver door closes or immediately for the passenger doors close. The BCM will turn off the courtesy lamps through the theater dimming feature. The BCM keeps the courtesy lamps on for 40 seconds after an alarm event is completed.

Instrument Panel and Front Floor Console Compartment Lamp

The inadvertent power supply voltage circuit from the BCM provides voltage to the instrument panel compartment (glove box) lamp and the Front Floor Console Compartment Lamp. When the compartment is opened, the compartment lamp switch contacts close providing a path to ground and the compartment lamp illuminates. If the operator inadvertently leaves the compartment door open with the compartment lamp ON, the BCM will turn all interior lamps OFF after 10 minutes has passed since any switch activation has been detected by the BCM.

Reading Lamps

The power supply voltage circuit from the overhead console module provides positive voltage to each reading lamp. When a reading lamp switch is activated, the switch contacts close providing a path to ground and the reading lamp illuminates. If the operator inadvertently leaves a reading lamp ON, the BCM sends a serial data request to the overhead console module to turn all interior lamps OFF after 10 minutes has passed since any switch activation has been detected by the BCM. Reading lamps are hardwired to BCM.

Rear Compartment Courtesy Lamps

The body control module (BCM) provides voltage to the rear compartment courtesy lamps through the rear compartment courtesy lamps control circuit. When the BCM receives a rear compartment door/lid open input from the rear compartment door/lid latch, the BCM applies voltage to the rear compartment courtesy lamps control circuit illuminating the rear compartment courtesy lamps. In the event that the rear compartment courtesy lamps were to remain illuminated for more than 10 minutes with the ignition switch in the OFF position, the BCM will deactivate the rear compartment courtesy lamps control circuit to prevent total battery discharge.

Rear Compartment Courtesy lamps may come on along with Dome lamps during a courtesy event if applicable.

Sunshade Mirror Lamps

The power supply voltage circuit from the overhead console module provides voltage to each set of sunshade mirror lamps. When the sunshade mirror cover is opened, a switch closes providing ground and the sunshade lamps illuminate. If the operator inadvertently leaves a sunshade mirror cover open with the lamps ON, the BCM will sends a serial data request to the overhead console module to turn all interior lamps OFF after 10 minutes has passed since any switch activation has been detected by the BCM.