@jwebb4616 The default position for RepRap firmware is that the part cooling fan is fan 0. That's because most slicers insert M106 into the gcode (without a fan number). But you can use any fan you like as long as you map it to fan 0 in the tool configuration (M563). So if you want to use fan 1 instead of fan 0, then add F1 to the M563 tool definition command. That way, whenever a gcode file is being printed which contains M106 commands (without fan numbers) the firmware will use Fan 1 instead of Fan 0. Just remember that whichever fan you decide on for part cooling, you must set it to non-thermostatic mode.
