To simplify and miniaturize a circuit constitution.
A radiator fan motor M1 and a condenser fan motor M2 are connected in parallel between the-drain of a FET 10 and the earth. The source of the FET 10 is connected to the positive electrode of a battery B through an ignition switch S1, a pressure switch S3 and a water temperature switch S4 are connected in series between the gate of the FET 10 and the earth, the gate of the FET 10 is connected to the output terminal P1 of a PWM control circuit 20, and a magnet clutch relay S2 is connected between the input terminal P3 of the PWM control circuit 20 and the earth. The PWM control circuit 20 detects ON/OFF of the magnet clutch relay S2, and outputs a PWM control signal of previously set duty ratio from the output terminal P1 when the magnet clutch relay S2 is ON.
HOSHINO TAKASHI
SUMITOMO WIRING SYSTEMS
SUMITOMO ELECTRIC INDUSTRIES