It is normal for the headlights to fog up after a rainy day. If the vehicle is driven on a rainy day for a long time, the fog will inevitably seep into the headlights. After the rain, park the vehicle in a sunny place to let the water vapor evaporate, and then turn on the headlights to use the vehicle. The heat generated by the lamp can be used to discharge the fog out of the lamp through the ventilation duct. This is also some common sense when using a car. I hope it can bring some help to the majority of car owners.