Foggy Windows Snowy Driving

Foggy Car Windows During Winter Driving TTD002

On today’s Auto Care Podcast episode Pat and I will present the who, what, when, where, how, and why of foggy car windows during winter driving. We decided on this topic when it was December in Boise ID. We were getting snow and fog in the valley and snow on the hills around us.

The ski area above Boise “Bogus Basin” had just opened it season. Many folks who love down hill skiing were heading for the slopes. We had record snowfall this winter. There is still a lot of snow on the hills so skiers will be traveling back to Boise for several months.

They will drive home with wet closes, during damp conditions, both of  can contribute to unsafe foggy window conditions. Even with an air conditioning on their car or truck operating correctly, it can be a strain to keep windows clear. A/C systems that are not working at their optimum can cause dangerous driving conditions.

Here are the 6 W’s of Foggy Windows

Who causes foggy windows – we are talking about two ways drivers or vehicle owners can cause them

  • The first way is by not operating dash controls properly which could include
    • Having recirculation on – it can recirculate moister within the cabin
    • Having air going to the windshield but not having the A/C compressor button pushed so the A/C system can’t dry the air
    • Not maintaining your vehicles air conditioning system. This could be ignoring recommended maintenance services to related components, or never having an Air Conditioning Service completed.

What causes foggy windows

  • The main culprit here is moisture! But coming in a close second is not having enough dry, warm air blowing on windows, which is caused by a problem with any number of components. We’ll cover these below.

When air conditioning failures cause foggy windows – here is a list of potential causes:

  • When you have a restricted cabin air filter
  • When Freon charge is low
  • When you have a slipping serpentine belt
  • When you have a worn A/C compressor
  • When A/C electronics fail
  • When mechanical component failures

Where you are driving and the conditions in your vehicle affect window fogging. Here are two factors relating to where you are when fogging occurs:

  • Driving during cold, damp winter months are the most likely conditions for fogging to happen. The extra moisture can be drawn inside the car by the air conditioning system.
  • But car occupants entering with wet close can add additional moisture. If they are breathing hard from exertion it can make it worse.

How defrosters prevent foggy windows.

  • Your car’s air conditioning system dries the air and directs that dry air to the windows needing the most protection from fogging, which is the windshield and front side windows.

Why air conditioning systems have internal problems

  • Hoses or seals leak Freon over time. Usually over a period of years.
    • Having your air conditioning system serviced can help catch Freon loss before it causes a problem.
  • Lack of cooling system maintenance can also contribute to air conditioning system problems. Both systems work together so a problem with one can affect the other.
  • Here’s a list ofcooling and A/C components that can cause internal or external air conditioning system problems.
    • Thermostats
    • Cooling fans
    • Radiators
    • Cabin air filters

So that is the list of causes of foggy windows during winter driving.

Here is a point you may appreciate after hearing the list of 6 W’s about windshield fogging.

When an air conditioning problem exists the default mode protects you

If your vehicle has an air conditioning problem while driving, car manufactures have designed the system to default with air going to the windshield. This is a safety measure to prevent the windshield from fogging when there is a problem.

Case of windows fogging with a working and maintained A/C system

Here is an actual problem with window fogging that Dave’s wife experienced with their back-up vehicle she likes to drive around town. It’s a 2003 Buick LeSabre with close to 350k miles.

We had some 20-degree weather recently and she had a hard time keeping the windows from fogging. I checked it out and found the thermostat was not closing enough to keep the engine temperature warm enough. So, even though the A/C system was working correctly, it had a hard time keeping the windows clear when the outside air temperature was cold.

If you would like some more information check out the articles on the website. If you are having window fogging problems or any heater problems give us a call at (208) 336-5315 or contact us on the website

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