Air only comes out of AC vents.
I get good heat and air conditioning from my front vents (AC vents), but when I select floor or defrost vents, the air still only blows from front vents. When I push the button for changing to defrost or any other position the light comes on but no change in air flow. What's the problem and how do I fix it? I did have it checked for faults at Auto-Zone but no faults came up