Air Filter Element with Included Installation Instructions. Location of Filter in Vehicle: Under Dash; Approximate Installation Time: 42 Minutes (Considered a Difficult Installation). Encountering a stale and musty smell in your vehicle? It might be your old cabin filter. Why Replace your Cabin Filter? A cabin filter works much like the air filter used with home furnace and air conditioning systems. Airborne contaminants may enter the interior of your vehicle through the heating and air conditioning system. Pollen and harmful substances inside a vehicle can be up to six times more concentrated than outside; Bosch Premium Cabin Filters prevent harmful spores and pollen from entering the vehicle interior and keep passengers and downstream HVAC components protected. Allergy and asthma sufferers may find the quality of breathing in their vehicles greatly improved after replacing an old cabin air filter.