Hello! We are in the process of finalizing our English version of the website. There may still be some small errors and poor texts, but we are working on it! Please feel free to contact us if you have any questions or concerns.
This post will cover all aspects related to condensation, moisture, or direct water in the headlights. Furthermore, we will delve even more technically into specific areas in the future and create a separate post for this.
First and foremost, we roughly divide “moisture” in the headlights into 3 categories: Moisture, condensation, and water.
Fog in headlights is completely normal and should actually occur when the external conditions are right for it.
Condensation in the headlights occurs when the “moisture / fog” gets out of hand. More and more moisture will accumulate inside the headlight, and it will start to bead on the inside of the glass – here we need to do something. We will address this in part 2, where the causes can be quite different. Condensation is a problem and must be remedied as soon as possible.
Water in the headlights should not occur and must be remedied immediately, as the water will damage reflectors, cables, and possibly electronics.
Moisture in headlights – normal
Condensation in headlights
Water in headlights
Moisture / Fog in the headlights – it is normal
Moisture in the headlights as shown in the picture above is “completely normal.” The moisture arises for several reasons, but technically it is when cold and warm air meet (a temperature difference of just 10 degrees is actually enough) – then condensation forms, which will fog up the glass – just like in houses without a ventilation system, when you sleep in a bedroom, the humidity level becomes high, and when it gets cold outside and warm inside, condensation will form on the windows inside – the exact same phenomenon occurs here. – If you want to know more technically about what can be done and why, then perhaps move on to part 2 about Condensation of headlights
You may also know it from when you take a cold cola / beer out of the fridge and place it in the living room, water forms on the outside of the product, it is also a “dew point” that is created when cold air meets warm air.
If you get a brand new car delivered, or buy a new set of headlights, you will often see it right after installation. The headlights come from a heated and warm place and are now driving in a cold climate, so a dew point forms on the headlight and the humidity in the air inside the headlight is higher due to the warmer air.
It occurs most often in spring and autumn when there are large temperature fluctuations. The same phenomenon occurs again. You may also experience it on a hot summer day if you wash the car and it is very hot in the headlight housing and you apply cold water to the outside of the headlight – then condensation will also form.
Another reason it often occurs on LED and Xenon headlights is that the headlights generate less heat, which also means it takes longer to “evaporate” the moisture inside the headlight. When the headlights are on, the air will be heated and expanded, here the air is pushed out through the headlight’s ventilation nozzles / ventilation openings – when the headlight is turned off again – the headlight will cool down and “moist” air will be sucked in and now there will be a high concentration of moist air inside the headlight.
Remember that 10 years ago, all cars drove around with a 55W halogen low beam bulb constantly. Today, LED daytime running lights are often used, which means there is practically no heat generation in the headlight itself to dry it out. Combined with the other factors, this means that you experience it more often today than with old cars.
There can be many reasons for fog – it can be anything from the car being parked where there is shade on one side of the car, and the other side being in the sun – it can be the construction of the car and the headlight, that the ventilation nozzles do not have the same amount of air around them for air circulation – or where there are heat sources for the headlight from the engine and the like.
If water beads form on the inside of the headlight, something is wrong and something needs to be fixed – that is the “dividing line.” See pictures below in part 2 – and read how you can fix the causes of condensation on the headlights.
Here you can see a headlight that has a “severe” moisture problem. Often it is actually not because the headlight is defective, but there can be several causes for the problem.
Headlights are not sealed, they are made with ventilation to be able to condense – therefore we start with the procedure to check for possible errors.
Dry out the headlight and try again – we always recommend removing the headlight and drying it out completely before troubleshooting – often this can actually solve the problem, simply because the moisture level in the headlight for an unknown reason has been so high that it could not get rid of the moisture again – often if a seal has been sitting crooked or not sealing properly.
Water in headlights
Here you can clearly see that there is water in the headlight – you can also see how the water has already completely destroyed the headlight.
Tips and tricks:
Lime beads on the headlight – A small tip is to look for lime streaks / beads on the headlight. If there are lime beads / streaks on the inside of the glass in the headlight, it is a clear sign that a seal is not sitting correctly or that the sealing is leaking as “tap water” is getting into the headlight – it is also a good way to check – if you can dry out the headlight and it looks “clean and neat” on the glass – then it is not external water that is getting into the headlight.
Silica Gel Bags / Moisture Bags – A small trick that can sometimes minimize or reduce fog / condensation formation is to place a bag inside the headlight – possibly attach it to the cover / cap of the headlight. Note, however, that as a rule, we do not recommend this solution, as it is an emergency solution to an “other” problem – but in some cases, it can improve the “climate” in the headlight and thus alleviate the problem – on some original headlights you will also find such moisture-absorbing products installed as standard.
Vehicle inspection with fog in the headlights – There must not be so much condensation / fog in the headlight that it destroys the vehicle's light beam, but a small amount of fog formation at the bottom of the headlight (which often quickly disappears with use) is OK.
Dansk
Svenska