Ok, this is going to sound strange. The fans blow out the dash vents just fine when I first start the AC. After a while (10 or 15 minutes) the fan is still running and sounds perfectly normal. However there is very little air being blown out the dash vents, or any vents for that matter. I hear it running, but no air movement. If I turn the speed control up to high it will start blowing normally again. If I then move it back to low speed it will again work for a while, then no air movement. Any thoughts where I should start looking first?