A control system for a vehicle with a plurality of selectively variable
characteristics includes a first button depressible to cause a first mode
of operation and a second button depressible to cause a second mode of
operation. In the first mode of operation, a rotary dial is rotatable to
cause variation of the first characteristic. In the second mode of
operation, the rotary dial is rotatable to cause variation of the second
characteristic. The control system thus enables a single dial to control
multiple characteristics or multiple vehicle systems, which enables a
corresponding reduction in the quantity of switches and other control
input devices in a vehicle passenger compartment.