2006 trailbalzer A/C Weird Noise

When I have the A/C blower going at 5 which is high setting the Airflow Makes a swooshing effect. it still blows air and is cold but fluctuates to a swooshing effect. any ideas? also when the car is at idle I hear a faint thumping sound that comes and goes from the passenger side under the dash any ideas for that as well?


Thanks Bill

Very tough to diagnose remotely, the actuator motor were problematic on these trucks, could make a noise.

Does the thumping only happen with the HVAC control head on? Does it go away if you turn it completely off?