I have a 2010 FX4. Turned on the ac yesterday and got a blast of hot air from the drivers side vents. The passenger side works fine, blows cold. I tried all the different settings from the climate controls on the dash and from the display screen, with no change to the hot air on the drivers side. Any help would be greatly appreciated. I would like to try and diagnose and,or repair myself without having to take it to the dealership. Thanks in advance

 

All of the vent control systems (doors) are operated by vacuum lines or motors that control where the airflow is supposed to go. The primary air plenum is, unfortunately, buried under the dash and requires almost complete removal to make the repair. Inspect all of the small vacuum lines at the firewall on the passengers side for damage. They are usually 1/4" red,green and white. Good luck