Horn Relay: Description and Operation

HORN RELAY
The Horn Relay, which is internal to the Integrated Power Module (IPM), is controlled by the Front Control Module (FCM) through PCI bus messages from the instrument cluster.

Body Control Module
Information Bus
Instrument Cluster / Carrier

These bus messages will be sent when either the horn switch is pressed which is hard wired to the instrument cluster, panic mode is requested from the RKE or for vehicle theft security reasons (if equipped). Under normal operating conditions, if the horn is activated for more than 30 seconds, the FCM will automatically deactivate the horn to prevent damage.

The FCM will reactivate control of the relay after a 25 second cool-down period. The relay control circuit is continuously monitored for malfunctions that the FCM will report as DTC's.