On mine it is in fuse box.It is black.Can they burn out.If so what happens ? Also does the arrow point up or down ?
Arrow points up. Yes they can go bad. If installed backwards they will blow almost instantly. The diode, as someone mentioned, is for the pto clutch.
On the diode near the metal tangs, is a locating tab made into the plastic. This designates the correct installation. However it can easily be installed backwards and blow the diode. Your dealer parts dept should have one. Common part to have.