Quite some time ago there was a thread here that addressed this topic, and I was hoping somebody could answer it again for me. I have a 16" spal fan connected to my xfi 2.0 box and have it set to come on and turn off at specified temperatures. I also added a toggle switch into the circuit in order to have the ability to manually control the fan if I ever wanted to. Somebody here had mentioned that this might not be a good idea because turning on the fan manually could send a spike to the xfi box, and that a diode could be added to keep this spike from reaching the box. If this is the case, can somebody please tell me where in the circuit this diode should be located and what type of diode etc. should be used? Any help would be appreciated, thanks! Just looking to prevent anything potentially harmful from happening..