Everything seems to be working properly. Blower is running at high speed, evap core is clear, and the doors are all working the way they are supposed to. I just don't have a lot of air flow through the vents. All of the 2003-2008 Chevy trucks I've driven will blow my hat off. This one seems to be only about half the flow of the newer ones. Is there a higher flow/efficiency blower available? Or should I just sell this thing and find another one that doesn't have 4000 problems?