Auto Headlamp has fog not all because of exter water

Headlamp are the eyes of a car and important for driving.But in winter,when have cold weather,it will always have some phenomenons that in the headlamp have fog.it is easy to cause hidden trouble to safety.

However,is it the quality problem to cause this situation?

The luminous source of the headlamp（HC-B-1503） will emit huge heat,lead to the air expand when hot and contract when cold inside the lens,then make huge air pressure.So in general will install flue or vent to avoid this problem.

During the rain season,when heavy rain or beginning of winter,after turn off the headlamp,the temperature decrease in the headlamp,the water molecules will be easy to enter in the headlamp through the vent or flue.

When the temperature is not balanced inside the headlamp(HC-B-1450-3),inside and outside the lens temperature difference is large,the water will flow from high temperature to low temperature.Then will condense on the inter lens surface ,usually in the down part in the headlamp.

From a physical perspective, there is a condensation core inside the headlamp. When dust and other particles enter the headlight chamber, the light distribution mirror or the inner surface of the lampshade, it creates conditions for the air molecules to find the condensation core because the surface is not smooth.

In addition,the complete headlamp sealed become worse.When refit the headlamp,some master not have much experience,will open the lens then close,the moist water will easily enter in the headlamp.

The most common is after heavy rain or the car wading,the engine cooling system will also cause fog in the headlamp.Because in closed engine compartment,the water is heated by high-temperature engine compartment into a large amount of water vapor, easy to penetrate through the vent pipe or vent to the interior of the headlight unit.

If it is too violent when wash the car,It is also the same reason to flush the engine compartment with a high-pressure water gun, which will increase the chance of water molecules entering the lamp chamber.

If the car headlights into the water, from the outside is not the vast white mist, but will appear in the headlight shade larger drops of water, will see the bottom of the lamp cavity obvious water.

This situation is mainly due to the sealing of the headlight assembly problems, or directly damaged shell, penetration and rupture. With the headlight fog easy to eliminate different, car headlights water is a serious maintenance problems, are generally difficult to repair, you need to replace the headlight assembly to completely solve the problem.

The best approach is to check the headlamp assembly airtight, open the headlamps after confirmation, about 15 minutes later, the use of headlamp bulbs of the large amount of heat emitted by the mist evaporated.