Help, fan relay stuck open
 

The main radiator fan (driver's side) is constantly on now. I can't get it to shut off unless I physically unplug it.

Someone on miataforums suggested I look for the fan relay. But I have no idea what he is talking about. All I see is a big bundle of wires under the hood that the fan wires merge into and that is it.

How does the fan on a 97 miata work. What switches it on and off?