Key Cylinder Lamp: Description and Operation

GENERAL INFORMATION
The ignition key-in feature provides the operation of the ignition key halo lamp when entering the vehicle. The driver side door ajar switch closing (door opening) when the ignition is OFF signals the Body Control Module (BCM) to turn ON the ignition key halo lamp. After the driverside door closes, the lamp remains on for approximately 30 seconds or until the ignition switch is moved to the RUN position. This feature is not available for at least 30 seconds after the ignition switch is turned OFF to prevent illuminating the key halo lamp when the driver exits the vehicle. If no doors are opened and then shut after the ignition switch is turned OFF, this feature is not available for 15 minutes.

CIRCUIT OPERATION
Halo Lamp
Power for the key-in lamp is supplied by circuit M1. This is the Ignition-Off Draw (IOD) circuit, and is protected by a 10 amp fuse located in cavity 13 of the junction block. Power for the M1 circuit is supplied by circuit A7 from the Power Distribution Center (PDC). This circuit is protected by a 20 amp fuse located in cavity G of the PDC.

Ground for the lamp is controlled by the Body Control Module (BCM) on circuit M50.

The Body Control Module (BCM) controls the operation of the halo lamp upon vehicle entry. When the driver's door is OPENED the door ajar switch CLOSES, and circuit G75 is grounded. The BCM sees that the door is ajar and provides a ground path for the lamp on circuit M50.