Buick/Olds: air flow location stuck, vacuum lines, buick century

Question
I have a 98 Buick Century - while the heat and A/C both work, the location control (i.e. upper vents, leg vents, defrost) seem to be "stuck" - meaning that there is small airflow through all vents but I cannot change it (it seems likely to be the feet/defrost setting).  What is the likely source of the problem?  perhaps a motor on the blend door?  

Answer
The blend door could be the problem.  This is actually called the actuator door, but usually that's it.  I would also try checking all of your vacuum lines and make sure that the clearing where the air comes in from your blower motor is clear.

Ray Barham

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