The AC is only blowing out the defrost vents

Question: The AC is only blowing out the defrost vents and not the front AC vents. What could be the problem?Optional Information: 2001 Jeep Grand Cherokee Answer; Automatic Climate Control: This is a common issue with the the Grand Cherokee's. This is caused by a failed electronic actuator that controls the mode(directional) door inside the air flow box mounted under the dash. Removal of the dash is required for this repair and can take up to 13 hours of labor. I do recommend having a dealer do this for you unless you are a seasoned mechanic. Manual Climate Control: A vacuum line going to the mode(directional) door manual vacuum actuator inside the air flow box mounted under the dash has cracked or the actuator has failed. Removal of the dash is required and can take up to 11 hours of labor.