Ventilation

The air distribution system provides fresh air ventilation for the passenger compartment in all operating modes. After being warmed to the desired temperature, the air is discharged from the outlets appropriate to the selected operating mode. When all windows are closed, the addition of outside air builds a slight positive pressure within the passenger compartment. The pressure forces stale air to leave the vehicle through a pressure relief valve below the glass in the rear of the cab after it has circulated through the passenger compartment.