2008 RAV4, manual air controls. My husband and I are in the middle of a 7 hour drive and we had the a/c going strong on the face vents. We were on the highway and all of the sudden the direction switched to the floor vents while we were still in "face" mode! We weren't touching any knobs, and don't believe anything fell into the vents. Now no matter what mode I select it only blows on my feet. Temp seems okay. I will say that in the past I noticed this knob had a lot of resistance when I would change air direction but didn't take notice of any patterns associated with this.