I am struggling to find some code to "borrow & edit (trial and error style)" to drive a 3 pin fan from one of the plug outputs on the R3 Motor shield.
It's not been for lack of effort searching, but possibly for lack of skill searching.
I have an "Enermax quiet" 12 V fan (plugged into the orange "out ~5"), and have a 12V DC source fed into the "v in" and "gnd" pins.
Were I smarter I would write up my own code, but unfortunately I am brand new to Arduino and code-writing.
I'm using the Mega 2560 R3 and the Motor R3 shield, if that makes any difference...