Good quality fans come with an adjustable temperature controller or are available as a separate purcchase. Positive and Negative wires from the fan go to the controller. I have the controller wired to the positive and negative terminals under the hood and it is mounted on top of the fender well. I wired in an inline fuse. The thermostat sensor wire goes from the controller to the radiator and is inserted between two of the fins. Fan comes with fasteners that go through the radiator fins to secure it. Instructions that came with the controller are very good. Straight forward easy job, no cutting, no drilling no relocating.

__________________
X5 4.6 2002 Black Sap, Black interior. 2013 X5M Melbourne Red, Bamboo interior
Dallas