The windshield delivers a blunt verdict: trapped cabin air has stayed too long when clear glass blooms into a milky film. Use it selectively. The little car icon is no permanent shield; it is a traffic filter, useful during exhaust-heavy stops, tunnels, smoke, or dusty roads.The smart move is selective use, not loyal devotion to one setting. Recirculation closes the fresh-air intake, so the HVAC s...More