@CrazyCreator thanks for reporting this, it's a bug. Expansion fans can't be controlled by sensors on the main board. This will be fixed in 3.6.0-rc.2.
@billsherenow It's usually either or. The 10 pin cable allows you to use the SD card slot in the PanelDue for Duets that support it. Otherwise the 4 wire cable is usually the better option.