2013 Cadillac ATS Owner Manual - Page 216

8-10 Climate Controls Operation Tips . Air Vents Adjustable air vents are in the center and on the side of the instrument panel. Clear away any ice, snow, or leaves from air inlets at the base of the windshield that could block the flow of air into the vehicle. Keep the path under the front seats clear of objects to help circulate the air inside the vehicle more effectively. Use of non-GM approved hood deflectors can adversely affect the performance of the system. Check with your dealer before adding equipment to the outside of the vehicle. Do not attach any devices to the air vent slats. This restricts airflow and may cause damage to the air vents. . . Move the slats (2) to change the direction of the airflow. Additional air vents are beneath the windshield and the driver side and passenger side door windows. These are fixed and cannot be adjusted. . Use the thumbwheels (1) near the air vents to open or close off the airflow.