A control circuit is provided for selectively determining multiple modes of operation for one or more electrical loads in an automotive accessory system. For a particular load, the circuit includes a switch and a microcomputer signal processing unit. The switch is typically of the momentary-action, dry type which provides a signal only so long as an actuating force is applied. The microcomputer repetitively, at brief intervals determines the presence or absence of such a signal indicative of switch actuation and further is responsive to either brief "momentary" actuation of the switch to effect a primary mode of load control or to a longer "dwell" actuation to effect a secondary mode of load control. The secondary mode of load control includes a characteristic which is determined as a function of the "dwell" duration. Such characteristics of load control in the second mode include the duration of actuation of directional lane-change lamps, the interval between sweeps of a windshield wiper operating intermittently and/or the intensity or brightness of illumination lamps.