Steering Mounted Controls Transmitter: Description and Operation

STEERING WHEEL CONTROLS

Some audio functions are available using the steering wheel controls. The steering wheel controls consist of multiple momentary contact switches that connect a series of resistors. When a steering wheel control button is pressed, a specific resistance value is noted by the DIM. This results in a generated voltage, unique to the particular button. The DIM alerts the radio that the button has been pressed, and the radio responds, just as if the corresponding radio front panel button had been pressed.

STEERING WHEEL CONTROLS - HVAC

The HVAC control module receives class 2 messages that the driver has activated a steering wheel control switch from the radio interface. The HVAC steering wheel control button controls driver set temperature increase and driver set temperature decrease.
^ Fan speed increase
^ Fan speed decrease
^ Driver set temperature increase
^ Driver set temperature decrease

The HVAC system interprets the set temperature switch on the steering wheel as if the driver had activated the same switch function on the HVAC control module (IPM).