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Why Do My Truck Windows Fog Up

Why do my truck windows fog up is a common question by truck drivers. Really, it is difficult to drive in when your truck windows fog up and you have to see in the side mirror also. Mostly wet conditions are responsible for this. So, for proper protection must be careful while bringing any humidity maker in the truck.

Why do my truck windows fog up? Moisturizers inside the truck are the main reason for windows fogging up. If the temperature of the inside is cooler than the outside or outside is colder than inside, it leads towards the dew point.

To avoid all this, you have to balance the temperature and air moisture content.

Why Do My Truck Windows Fog Up
Why Do My Truck Windows Fog Up?

Why do my truck windows fog up?

Excess smoking can also be the reason after mixing up with the dirt. Smoking and dew point is the cause of fogging up by involving factors like humidity, heat, condensation, and off-gas plastics.

Some major factors that cause fogging up truck windows are given below:

Humidity Can Cause Truck Windows Fogging Up

There is more moisture in the warm air and that’s the result of inside humidity. Humidity can be caused by wetness inside a truck cabin.

The wetness can be of wet clothes or may be due to the weather conditions i.e. when there is rain or snowfall outside.

Sometimes eating in the truck can also be the source of windows fog up. Even hot fast food can enhance moisture level intensity in the truck’s cabin.

All this humidity condenses inside glass windows as it is a cooler environment outside. You can adjust the humidity level by recirculation of heater/cooler with the outer environment.   

Off Gas From Plastics

Most new vehicles have these kinder issues. It is because when you park outside under some sunlight on a sunny day, plastics or vinyl used in seat covers or present in any form in the cabin causes trouble.

The heated plastics release off-gas in the form of haze which smoothens on the windows especially on the windshield.

In these situations, you notice that even you are cleaning enough the outside/inside but there is still the problem. You can easily avoid this once by opening all doors and then filters the air throughout the truck to release all the off-gas.

Engine Coolant

The engine can be a problem if you are having any leakage inside from any tube. This tube may be of your engine coolant pipe. And it leads towards a greenish haze on the windshield.

You can also check it by yourself as it has a strong smell or you can go for a mechanic to check this issue.

Make sure to cure this problem as soon as possible as it contains harmful gases coming into the truck cabin.

Avoid any kind of further driving in this situation till a checkup from a mechanic due to its threat towards breathing.


During the winter season, there is maximum dampness in the air and the temperature is also near to zero degrees centigrade. And warm air, of passenger’s exhaling or through any other source, contacts with the low temperature to produce moisture in the cabin. That leads to condensation having an impact on the window.

Mostly in the early morning on summer days, when you turn on your truck’s cooler it creates a difference in dew points and that results in condensation.

It is because the humidity inside a truck needs a way to be out and condensation with a due difference gives it opportunity. The weight of the droplet decrease and it spreads at the window in the form of gas.

Smoking can fog up truck windows

Smokers always have issues with the window screen whether it is because of letting the smoke getting out or get rid of its smell.

Carcinogens found in the cigarette spread through the smoke and they found no way to get out of the truck.

These particles remain on the windows unless you don’t wipe them out. These also create dirt on the screen i.e., also the cause of fogging.

How to protect truck windows from fogging up

No worries! Here are few things you might try to prevent your truck windows from fogging up:


Generally, fogging happens because of temperature differences. For example, when the temperature of the window screen is colder than the air inside. So it means we have to prepare our minds for these conditions to get the job done easily.

We cannot lower the temperature as a whole, all we can do is to lower the inside temperature but for that, we have to keep the heater on.

So, another simple solution is to keep a bottle of warm water with yourself and pour it on the screen when needed.

Reduce The Moisture

The second most important factor after the temperature is wetness inside your truck. Avoid every type of wet thing from bringing into the vehicle. Even a few drops of snow or rainy water can create a fuss for you.

Must be careful about the mats, if they are silly or getting dull, change them within no time.

Before driving if you have walked under certain rainy weather conditions then there are more chances of moisture coming inside. Water coming with your umbrella and shoes or your wet clothes can be the main problem.

If you are having any holes in the window then cure these things. You are more likely than not entering some extent of moisture inside your truck, and that will make defogging a genuine agony. Think about replacing your windshield.

Clean The Windows

Dirt has a direct relation with fogging and can be troublesome during extreme weather conditions. The dirt after mixing with fog or any other water vapor will be long lasting or we can say more hesitant to leave.

You can use these screen-protecting sheets to protect windows from permanent spots resulted from fog or dirt. Do proper measures and connect with the consultant if you still having issues with these.

Read also;

Can a truck run without a catalytic converter

Why Do Guys Squat Trucks

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