Windows naturally fog up when there is a difference between the temperature and humidity on the outside and inside of the glass pane. The warmer and moister air on one side condenses against the cool window surface. If this condensation occurs on the outside of the window, all you need to do is turn on the wipers to whisk moisture away; when the condensation occurs inside, however, there can be a problem.
While this is a natural occurrence, vehicles have systems in place to both prevent and eradicate foggy windshields because it interferes with the driver’s ability to see the road, causing a safety hazard. Although defrost and anti-fog systems are standard components of modern cars, they are not immune to breakage or poor performance from wear and tear.
Common reasons for this to happen:
Broken blower or blown fuse: If you cannot feel any air come through the vents by the window when you turn on the defroster or anti-fog system, this indicates that the blower isn’t moving any air. While this could be due to a blown fuse, it can just as easily indicate that the blower itself is faulty. A mechanic with the proper diagnostic equipment will be able to quickly discern which one is the cause of the problem.
Faulty heater core: If, when you turn on the anti-fog system or defroster, you can feel cold air going through the vents, then the air is not being warmed properly. This points to a problem with the heater core.
Low coolant: When your engine coolant is low, it can actually impact your defrost system negatively and mimic an issue with your heater core by putting out only cool air through the vents. You can easily remedy this (or at least rule it out as a potential cause) by simply checking your coolant level underneath the hood.
What to expect:
A top-rated mobile mechanic will come to your home or office to determine why your window is fogging up. This will include checking your window for any damage or faulty seals, as well as inspecting your defrost and anti-fog system components.
After the inspection, the mechanic will provide a detailed report that describes the source and cause of the window fog issue, along with the scope and cost of the necessary repairs.
How important is this service?
Although your window fogging up doesn’t prevent you from driving from point A to point B, it is important to take care of the issue as soon as possible, as a fogged-up window impedes visibility and makes driving less safe. Also, whatever is at the root of the problem has the potential to affect other vehicle components, which could ultimately increase the cost of repair if left unattended.