S7 Turn on the headlights in rainy days. Is it normal to fog inside the headlights?

Headlights emit a lot of heat when turned on. After the air in the lampshade is heated, the pressure inside is slightly higher than that outside. At this time, if there is a gap somewhere, the pressure will be released and the air in the lampshade will become thin. Once the temperature drops after turning off the lights, the pressure in the headlights will be lower than the external atmospheric pressure, so some air will be sucked back through the gap to make up for the balance. If it happens to rain or be wet, water vapor can be easily drawn into the headlights. The next time you turn on the headlights, most of the air will be squeezed out, and then some water vapor will be inhaled, and so on, and the water vapor will accumulate more and more. Knowing the cause of the water inflow, once the headlights are flooded, we have a way to deal with it. If there is no trauma to the headlight, it is best to replace the bulb sealing cover or fill it with glue to enhance the blocking effect. If it is difficult to determine where the water leaks, you can use the following methods to test: choose dry weather, turn on the headlights to dry the fog inside, then turn off the fire and turn off the headlights, and spray water on the suspected place with a water pipe, such as the bulb sealing cover. After a few minutes, if there is fog in the headlight, it can be concluded that the light bulb socket is not tightly sealed, which leads to water leakage, otherwise it is just a problem with the adhesion of the big lampshade. It should be noted that when gluing, it is better to remove the whole headlight, clean the bonded part of the lampshade, and then glue it after drying, which is more reliable.