Horn System (Service Information): Operation: Operation

The horn system operates on battery current received from an output of the Totally Integrated Power Module (TIPM) through a high side driver. The horn system circuit is designed so that the system will remain operational, regardless of the ignition switch position.

The vehicle operator can control typical horn system signaling through the horn switch within the hub of the steering wheel. When the Driver AirBag (DAB) trim cover is depressed, it provides a hard wired analog input to the Local Interface Network (LIN) slave node integral to the speed control switch pod. The LIN slave node then sends electronic horn switch status  messages to the LIN master node integral to the ElectroMechanical Instrument Cluster (EMIC) (also known as the Cab Compartment Node/CCN). The EMIC then relays an electronic horn request  message to the Totally Integrated Power Module (TIPM) over the Controller Area Network (CAN) data bus.

In addition, the Remote Keyless Entry (RKE) system will send electronic horn request  messages to the TIPM over the CAN data bus in response to inputs received from the RKE transmitter through the Wireless Control Module (WCM) (also known as the Sentry Key Immobilizer Module/SKIM or the Sentry Key REmote Entry Module/SKREEM). Lastly, as the Vehicle Theft Security System (VTSS) controller, the TIPM can activate the horn system based upon programming and both hard wired and electronic message inputs from the various VTSS components.

The hard wired inputs and outputs for the horn system may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information. However, conventional diagnostic methods will not prove conclusive in the diagnosis of the speed control switch pod, the EMIC, the WCM, the TIPM or the electronic controls and communication between other modules and devices that provide features of the horn system. The most reliable, efficient and accurate means to diagnose the speed control switch pod, the EMIC, the WCM, the TIPM or the electronic controls and communication related to horn system operation requires the use of a diagnostic scan tool. Refer to the appropriate diagnostic information.