The instrument panel cluster (IPC) and the driver information display (DID) in the raidio illuminate the door ajar indicator when the body control module (BCM) detects that any of the four doors is open. The IPC and DID receive a low speed GMLAN serial data message from the BCM requesting illumination. If the vehicle is shifted out of park with a door open, the BCM sends a low speed GMLAN serial data message to the IPC in order to activate an audible warning.