A static switch for DC motors of climate control units, comprising a signal side and a power side, which are mutually separated by means of optoisolators, the side comprising in input at least one terminal for a motor on/off signal and a terminal for a pulse width modulation signal PWM to provide the amplitude modulation, on the power side, of a motor speed signal, the switch comprising a precharging device which has a control terminal connected to a power-on optoisolator and a precharging current supply terminal connected to a motor power supply pole, the switch further comprising at least one power-on transistor connected to the same motor supply pole of the power supply terminal of the device, so that a voltage applied across the power-on transistor that exceeds a certain threshold switches off the motor power-on transistor.