Switch, Horn: Operation: Operation

When the Driver AirBag (DAB) trim cover in the center of the steering wheel is depressed, the springs between the electrically conductive horn switch contacts are compressed allowing them to contact each other, closing the switch circuit. When the DAB trim cover is released, the springs between the switch contacts expand, opening the switch circuit.

When any one of the four sets of horn switch contacts forms a completed circuit, a horn request signal is provided to the Local Interface Network (LIN) slave node integral to the speed control switch pod in the right horizontal spoke of the steering wheel. The LIN slave node sends an electronic horn switch status  message to the LIN master node and Controller Area Network (CAN) data bus gateway 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 CAN data bus, and the TIPM activates a high side driver to energize the horn feed circuit.

The horn switch as well as the hard wired output circuits for the horn switch may be diagnosed using conventional diagnostic tools and procedures. Refer to the appropriate wiring information.