An active noise control system for use onboard a vehicle normally provides noise
cancellation of engine sounds. The speaker of the active noise control system also
emits a horn sound responsive to appropriate commands from a controller that receives
a horn switch signal from a horn switch supported on a steering wheel assembly.
The active noise control system controller enters a power saving mode when the
vehicle ignition is turned off and the vehicle is not running. A horn switch activation
during the power saving mode wakes up the controller so that the controller unmutes
an amplifier and drives the speaker to emit the desired horn sound.
