03Tahoe that only blows air through the front defrost attempts to blow through the front vent clicks goes bak?

I have an 03 Tahoe. The front air is only blowing out of the defrost vents. As soon as the vehicle is cranked it will blow out of the front vents but makes a clicking noise like it is hanging on something and then goes back to the defrost. It does not matter where I turn the nob it only blows out of the defrost. I was told it could be the actuator under the front dash. Not sure.