Moisture in headlights: Causes and Solutions


Every car owner has probably faced the problem of headlight fogging. It is more than just annoying, it is a serious malfunction that can compromise not only your comfort but your safety as well. In fact, in most cases, the accumulation of moisture in the headlights is a normal and quite acceptable phenomenon. However, it is urgently important to find the reasons and treatment as soon as possible. Go on reading and you will find a quick guide of how to get water out of your headlights right here.

Why do headlights get foggy?

Headlight fogging is a serious but common problem. Ignoring it can cause not only additional costs but also affect ride comfort and safety. The first step to getting rid of it is to find out why this is happening.

This phenomenon sometimes happens within normal limits and there is no need to worry. For example, condensation inside headlights can appear after the night parking in a cool damp area. In this case, it will dry out on its own right after you start off and drive for a while with the light on. Slight haze can also appear after the car wash or after the long night drive when your hot headlights start cooling down. Such condensation is not scary, because it usually evaporates on its own. However, if you notice a substantial amount of moisture in your headlights it is time to find its causes and take necessary measures.

Condensation in the headlights may appear for the following reasons:

  • Clogged hole in the ventilation system. There are two plastic tubes on the back of the headlights. They serve as ventilation passages in the light unit. Their clogging prevents the outflow of moisture from the body of the headlight and it looks foggy.
  • Incorrect replacement of a bulb. Especially if it was performed in wet conditions. 
  • Cracks, chips or other micro defects in the body or glass of the headlight. All these damages can contribute to the inlet of water into the device.
  • Dry sealant. Glass must be in very tight contact with the housing, which can be achieved with a good headlights sealant. Sealants tend to dry over time and as a result, water can get into the headlight.

Is Fogging Dangerous?

It is undoubtedly dangerous. Untimely diagnosis and delayed elimination of this problem can have negative results.

First of all, water in the headlights distorts light distribution, which interferes with both the driver (the illumination of the road falls) and other participants of the traffic (they are blinded). All these malfunctions can cause an accident.

What is more, with the increased moisture concentration, all the elements inside the headlight unit can be corroded. Many parts can also suffer from oxidation and rust, and lose their properties over time. Besides, the oxidation of the contacts disrupts the normal operation of the electronics and can even cause a short circuit in a car system.

How to Get Moisture out of the Headlight and Eliminate Causes of Fogging?

Getting water out of a headlight with the help of a heat gun

One of the easiest ways to dry foggy headlights is to use a heat gun or an ordinary hairdryer. This must be done carefully, otherwise, the plastic may deform under the influence of high temperature. You should constantly move the heat gun and keep it not close to the headlight.

This method of headlights cleaning is rather good because you do not need to remove the headlight from the car. However, it will give you just a temporary improvement to the problem. The more important thing is to prevent condensate appearance in the future.

The inspection of the headlight

The quality solution to this problem is impossible without a thorough inspection of the headlight. To check the device, you must:

  1.  Remove terminals from the battery;
  2. Unscrew all the bulbs;
  3. Clean the case of the headlight with a soft rubber cloth;
  4. Check for cracks in the joints. If it appears that your headlights get foggy due to the cracks in seams, you should clean it first and then put a new headlight sealant;
  5. Inspect a case for micro cracks. To do this, you should immense this item in water. There will be air bubbles in the places of cracks. Use colorless sealant or glue to restore the headlight part;
  6. Check the ventilation valves in the breathers. If they are clogged, you should remove dirt from them.

How to reseal the headlight?

If it appears that your sealant has dried up, to seal your headlight you must:

  1. Clean the surface and remove the old sealant. It can be done either by heating your headlight in the oven (for 20 minutes at approximately 230-250 degrees Fahrenheit) or by softening the old sealant with a heat gun;
  2. Remove the headlight case;
  3. Apply new sealant, press it down and dry.

How to avoid common mistakes in the process of cleaning headlights

First, you should keep in mind that all the parts of headlight construction are rather delicate, so they can be easily broken. That is why you should be extremely careful while working with headlamp components.

The second important point concerns the temperature of heating equipment. The overheating of lenses, reflectors, glass and some plastic parts can transform their construction.

Don’t touch the reflector, as its surface is very sensitive and you can make it even worse. Try not to direct streams of warm air onto the reflector as well. Otherwise, it can be damaged.

3 Effective Tips to Prevent Headlight Fogging

There are some useful life hacks to save your headlight from moisture:

  • Make it a rule to turn off lighting devices in advance before washing your vehicle so as not to cause condensation due to strong temperature differences. If possible, do not drive out from the wet box.
  • Check the condition of the ventilation valves from time to time. Remove dirt, which can be accumulated in them. Pay attention to the places, where wiring enters the headlamp housing. The seal must sit firmly in its position.
  • Some manufactures put silica gel granules in the housing of the headlights. This substance absorbs moisture and protects headlights from getting wet. As a rule, this is a small bag with absorbent material, the lifetime of which is limited only by the life of the headlight itself. It is not difficult to make such a device yourself by placing silicone granules in the headlamp housing. If you decide to try this lifehack, make sure you do not put it near the light bulb, as it will melt there.

As you may see, cleaning cloudy headlights is not an easy task, but still, it is possible. We hope that our recommendations will be useful for you and answer all your questions on how to clean your foggy headlights. Do not forget that it is necessary to make a try, if something goes wrong you can always consult a professional.