2011 Chevrolet Impala Owner's Manual - Page 207

Climate Controls 8-5 Air Vents Use the thumbwheel located below or to the side of the outlet, to change the direction of the air flow. . Operation Tips . Clear away any ice, snow, or leaves from the air inlets at the base of the windshield that may block the flow of air into the vehicle. Use of non-GM approved hood deflectors may adversely affect the performance of the system. Keep the path under the front seats clear of objects to help circulate the air inside the vehicle more effectively. If the airflow seems low when the fan is at the highest setting, the passenger compartment air filter, if equipped, may need to replaced. For more information, see Passenger Compartment Air Filter on page 8‑5 and Scheduled Maintenance on page 11‑2. If fogging reoccurs while in vent or bi-level modes with mild temperature throughout the vehicle, turn on the air conditioner to reduce windshield fogging. Maintenance Passenger Compartment Air Filter The vehicle has a passenger compartment particulate air filter. It is located in the engine compartment, below the air inlet grille on the passenger side. The filter traps most of the pollen from air entering the climate control system. It needs to be changed periodically to ensure system performance. For information on how often to change the passenger compartment air filter, see Scheduled Maintenance on page 11‑2. . . .