Why Does the Dashboard Fog Up Inside?
2 Answers
Fogging on the car dashboard occurs due to high humidity inside the vehicle. Here are some related explanations: 1. Opening windows for air convection: If the fog inside the car is not too heavy, you can slightly open the windows on both sides to create air convection between the inside and outside of the car. This reduces the temperature difference and gradually dissipates the fog. The principle of this method is the same as using the air conditioner to blow cold air, but it does not increase fuel consumption. However, the downside of opening windows for convection is quite obvious—it's not suitable during rain or snow, on highways, or when the fog is heavy. Additionally, opening windows lowers the temperature inside the car. 2. Air conditioning system: For most car owners, using the air conditioning system to defog is the most common method. Almost all cars on the market today have air conditioning vents located under the front windshield. Simply adjust the air conditioning to the appropriate setting to use the air flow from the vents to remove the fog.
As a long-time automotive repair professional, I've encountered numerous cases of dashboard fogging issues. The root cause is typically the temperature difference between the interior and exterior, causing moisture to condense on plastic surfaces. For instance, when a car is parked overnight in a humid location, the morning startup creates a temperature differential that leads to condensation. Check if the door seals are aged or cracked, or if window seals have loosened, as these can allow moisture infiltration. Improper air conditioning system settings are another common factor - using recirculation mode on rainy days actually introduces more humidity. Additionally, older vehicles may have heater core leaks, where antifreeze seepage causes internal moisture buildup. My recommendation is to first use the AC at high fan speed in recirculation mode for dehumidification. If this doesn't resolve the issue, inspect the drain holes for blockages and visit a professional shop if necessary. Regular vehicle cleaning and maintenance of sealing components can effectively prevent this annoying problem.
