When I start the car, there is a noise that sounds like an air pump coming from the frond dash. The air that comes out is not hot, regardless of water temp. Could there be a motor or vacuum positioning that controls the vent for comfort heating?
Your response was right on the button. I went today and they found a "air mixing actuator" was not responding. Cost of the actuator was 165.00 and the labor was 150.00. The actuator was inside the dash behind the glove compartment..... a real booger to get to and NOT a job for me. Thanks for the help.