@bobrhett is the fan connector the only thing that is different? What are the numbers on the original motherboard? You can always contact iFixit customer service https://help.ifixit.com/category/133-contact-ifixit-customer-support and see what they suggest. I would think that the model of your replacement board probably always comes without the fan connector. To fix it I would think you either get a different board (same model as your old ones) or you test the solder pads on the new board and see if it even carries power for a fan. Then transplant the connector. I am sure there is some other power source for the fan but you'd be missing the tach for the fan etc. (if it is a more than a 2wire fan)