RAM 2500 Truck 2WD L6-5.9L DSL Turbo VIN C (2002)
Cabin Ventilation Duct: Description and Operation
Fig. 1 HVAC System Airflow
HVAC SYSTEM AIRFLOW
Outside air enters the vehicle through the cowl top opening at the base of the windshield, and passes through a plenum chamber to the HVAC system
blower housing. Air flow velocity can then be adjusted with the blower motor switch on the a/c heater control panel. The air intake openings must be
kept free of snow, ice, leaves, and other obstructions for the HVAC system to receive a sufficient volume of outside air.
It is also important to keep the air intake openings clear of debris because leaf particles and other debris that is small enough to pass through the cowl
plenum screen can accumulate within the HVAC housing. The closed, warm, damp and dark environment created within the HVAC housing is ideal for
the growth of certain molds, mildews and other fungi. Any accumulation of decaying plant matter provides an additional food source for fungal spores,
which enter the housing with the fresh air. Excess debris, as well as objectionable odors created by decaying plant matter and growing fungi can be
discharged into the passenger compartment during HVAC system operation.