I had the option to connect the controller to the ignition. I did not so that it would run when the ignition is off to reduce heat soak. If you want to wire to the ignition it is only necessary to find a wire that is only live when the ignition is on. My fan is intentionally not a variable RPM fan. I want it on or off. With the stock electric pusher still in place I didn't feel the need to have the aftermarket fan come on when the air is on. If the air conditioning causes the engine temp to exceed the controller setting the aftermarket fan will come on. I have the controller set so the aftermarket fan comes just before the electric fan does. Stock electric fan is never needed to cool the engine.

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