Can't turn off fan using PWM and analogWrite(x, 0)
If you are working with the AC motor, then it is probably works even PWM cable is not attached. In this case there is no reason to use &quot;analogWrite(PIN, 0)&quot;.  It will not work.
&quot;An external resistor divider connected to the VMIN input sets the minimum fan speed by fixing the minimum PWM duty cycle (1.25V to 2.65V = 0% to 100%, typical).  It depends on controler card manufacturer. check datasheet&quot;
If you cant find datasheet like me then check how others do. There is diagram of &quot;HW-753 Signal Generator Module&quot; below. As you can see between VIN+ and PWM there is 1k Resistor and both wired to an NPN, also the mid leg of NPN passing 1k resistor while going to pwm to protect the card. Also 3rd leg is wired to gnd. So it is not the same thing I was doing before. If you work with AC then you must always consider that and just forget what people say. Do not drown like me. I hope it will helps someone.