What causes fogging inside a car's LED lights after washing?
2 Answers
There are several reasons why fogging occurs inside a car's LED lights after washing. Light structure design: The more regular the internal structure of the light and the larger the gaps between components, the faster the air circulation, making it less prone to fogging. Narrow areas have the opposite effect. Physical reasons: The presence of condensation nuclei inside the light, such as dust particles entering the lamp cavity, lens, or inner surface of the cover, creates conditions for water molecules in the air to condense due to the rough surfaces. Poor sealing of the assembly: During headlight modifications, inexperienced car owners may open and close the lights improperly, allowing moist air to enter the lamp cavity.
After the last car wash, I noticed condensation inside my LED headlights, which is actually quite common. Aging or improperly installed headlight seals can allow moisture to seep in when using high-pressure water jets during washing. This is especially noticeable during seasons with large temperature differences between winter and summer, as the alternating hot and cold conditions inside and outside the lens can cause water droplets to form. My car is over three years old now, and the sealing rubber has indeed hardened a bit, so it seems I need to replace the gasket. Here’s a handy tip: after washing the car, you can leave the headlights on for about half an hour to let the heat dry out the interior. If the condensation hasn’t cleared by the next day, it’s best to take it to a repair shop for inspection—too much water ingress could damage the circuitry. Also, it’s a good idea to check if the headlight drainage holes are clogged with mud.
