Hello! I would suspect a blend door or actuator has failed, not the heater valve.

Hi David, It is possible that is the main problem. For accurate diagnostic and repair, we recommend referring to a trusted vehicle specific repair manual for details about this particular part for replacement and installation. Still, it is best to consult your trusted local auto repair shop or dealership for this if you need to. You can find more information here as well: https://www.carparts.com/blog/why-you-should-always-consult-a-repair-manual/

Hi, To check for other options of Heater Valve for your Mountaineer please use our Vehicle Selector — which can be found towards the top of the homepage as well as all category, search results, and product pages — can help verify if a part will fit your specific application. To enter your application, simply select your vehicle’s year, make, model, sub-model, and engine type and click “Go.” Once your application is selected, you’ll see a “Guaranteed to Fit” badge if the part will fit, and we recommend that you also double-check Your Vehicle Fit Details as well as the Vehicle Fitment Information table on the product page.