Mount the actual control box with relay and fuse on the inner fender. Following the detailed instructions included with the control unit, wire up the fans to the control box, being sure to include fuse holders in each fan line and “reverse” the wiring since the fans are being used as “pusher” models. Connect the ground wires from both the fans and the control to a clean connection on the body. Then wire up a +12 volt line directly from the battery or starter terminal (on cars with battery in the trunk) to the control box. If you want the fans to run when the ignition is off, you will need to connect the wire that would normally go to the ignition to the +12V line coming directly from the battery. If you want the fans to only run when the ignition is on, you will have to run that wire inside the car and connect to the proper terminal on the fuse box.

Control box mounted on fender. Adjustment screw is hidden in this photo.

Finally, connect a wire to the green A/C compressor control line that attaches to the clutch on the A/C compressor so the control unit will know when the A/C is turned on. Other than making an adjustment to the control box, you are done. To semi-accurately set the temperature control point, I used a cheap meat thermometer inserted into the radiator core next to the control box probe. It took a couple of tries to get it where I wanted it.

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