Hey forum. I'm new to this forum and this is my first post. I need help with my blazer. I'm replacing the heater core right now and have already taken it out. I have a secondary issue I want to fix before I put it together. The issue is that the air doesn't change between face, floor and defrost when I adjust the controls. The a/c works fine and turns off and on depending on the control setting just fine. Also, no hange from a/c and a/c max setting. Any ideas?