Vent Door Actuator?

[harbison]

2009 Yukon XL with auto AC
Passenger and rear AC work fine. Drivers blows hot but not always. Sometimes closing vents will switch it back to AC. Intermittent. Is actuator sticking, going out or something else. Thanks

 

[LTLux]

Blend door actuator. Do a search, a lot of info on how to install. Not verry hard.