Circuit/System Description

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 dome lamps are controlled by two ways, by the switch on the A98 Front Overhead Console Assembly 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, Dome Defeat switch and Door Cancel 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. When the Door Cancel switch is enabled, the Dome Lamps will not turn ON when the vehicle doors are opened. An indicator lamp will be present to inform the driver that the Door Cancel switch is enabled.

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