I have a 2006 BMW X5 3.0i and today when I started my vehicle up in 80 degree Fahrenheit I noticed there was no air coming from the front vents. In fact no air coming from the floor vents or the top defroster vents. Just only the rear vents. Is this a final stage resistor? Or do these E53s have blend doors that could be the problem? The climate control panel works perfectly I tried max a/c button and front defrost button and nothing no air at all.