This may be a question for the Cooling/Heating forum, but I think its different on Excursions. I have a 2000 7.3L Turbo Diesel and the only vents that work are the defroster ones. I cannot get it to switch to floor or vent mode regardless of what position I put the heater control into. Whether its AC or Heat, it only blows out the defroster vents. This Excursion is NOT climate controlled and I don't hear any vaccum leak. Any ideas on how to repair this? It appears that the default position (when something is wrong) is defrost. Thanks, Ray

 

I ad the same thing happen on my 05. It was a actuator under the hood that switches between the vents.
I didnt dig too deep into it because it was still under warranty so I am just going off of what they told me.
Zach

 

Zach, thanks. Does anyone know where this actuator is located on the Excursion?