Exterior Lighting System
WARNING: This page is about a different car, the 2004 Dodge Pickup and 2004 Dodge Cab & Chassis. However, it is still accessible from the selected car via links, so may be relevant.
The Instrument Cluster monitors the Headlamp Switch and Multifunctions Switch on its MUX line. The Instrument Cluster sends a PCI bus message to the Front Control Module (FCM) to actuate the Headlamps ON when the ignition switch is ON and when an open or short failure occurs on the headlamps switch input circuit to the instrument cluster. If the exterior lamps are left ON and the ignition switch OFF for more than 5 minutes, the FCM will turn the exterior lamps off. This feature prevents the battery from being discharged when the Exterior Lamps have been left ON.