Summary I got tired of the jumble of alligator clips, jumper wires, external power supplies, chewing gum and baling wire and other kludges just to get MOAR fans to blow on my PLA prints on my MM3. So I quickly designed this little switch plate in Sketchup. Simply run some extra DC and ground lines from the power supply, install the switches and banana jacks of your choice, and you have a neat solution to the problem. Sketchup file included so you can make changes as desired. You may wish to label your switches some other way or using some other language for example. I suspect this would work for other flavors of Mendelmax printer as well as other types of reprap printers, though I have not tried it with anything but an MM3.