composed by man Cunningham in Cooling,Cooling,Detailing,Fluid Leaks,Heating,Heating,Maintenance,Troubleshooting
*
*
*
*

The recirculation button is designed to prevent exterior air native coming into the cabin. Useful for maintaining fumes out and getting the cabin come the preferred temperature quickly. However, the cabin air quickly goes stale and also moisture-laden as passengers breathe. The recirculation switch wasn’t designed come be used for an ext than five minutes or so.

You are watching: Why do windows fog up when making out


Some solution will automatically turn it turn off after a collection time period. Breathing in stale wait is clear not an excellent for the body and also it additionally causes the moisture-laden air come condense choose crazy on the windows.

Two icons are typically used to determine the recirculation button. The modern symbol in the photo above and the enlarge symbol in the picture below.


So use the recirculation button sparingly and never when trying to clean the fog indigenous the windows.

Wet Dog Or Clothing

My father’s dog Sammy can’t happen a puddle and he’s in it, he’s a messy mutt, however we love him. Anyway, we all know what happens once we’ve wet panting dogs in the car. It’s impossible to store the home windows clear, there’s so much moisture in the air, even the smartest HVAC mechanism struggles.


Wet clothing snowy boots, wet floor carpet all add moisture come the cabin, and that will revolve to fog. Keeping the moisture within your auto to a minimum will assist control foggy windows.

Water Leak


A water leak right into the auto is an ext common in older dare than newer ones, but new cars aren’t immune. You already know the moisture within the vehicle will reason foggy home windows no matter how good your heater is.

So how does water get into the car?

The most usual ways include:

Blocked sunroof drainsDamaged sunroof sealBlocked A/C drainFaulty windshield sealerBlocked scuttle panel drainsBroken bulkhead human body sealerDamaged door home window sealsDamaged stems seals

If you’ve been to the auto wash and an alert a trickle that water coming in, there’s a great chance rain can obtain in too. Examine your floor mats for dampness, or better, lift her carpets in ~ the absent panel, just sufficient to acquire your hand underneath.

If you think you might have a leak, check out this article “Car floor wet under mat”, it covers some of the basic fixes most civilization don’t recognize about. A leak will should be repaired as shortly as possible, as it will ultimately lead come expensive electric issues.

Car heater leakHeating device Leak

A heater device leaking is a nuance yet a heater that leaks inside the cabin is a total pain in the jacksie and also a serious health and wellness hazard.


The engine heats coolant (liquid anti-freezing formula & water) and pumps it about the engine and into the cabin whereby it passes through the heater core. The main point resembles a mini auto radiator and also in older car often establishes a small leak.

As the core is positioned inside the car, hidden behind the dashboard. The leak pools in the former foot-wells, soak right into the insulation and carpets.


The leak will generally go undetected, however, the passengers may notification the complying with symptoms:

Constant fogging the windows.Sat Nav won’t stick to the windshield.Sweet smell inside the car.Car coolant needs topping increase regularly.Heating temperature temperamental.

Regular users of the car emerged a chesty sneeze that won’t shift. Obviously, your health comes first, so addressing the leak is a priority. A leak that goes undetected can additionally cause engine frost damage, specifically if the user tops up coolant with directly water.

Heater Fault

Modern heaters – HVAC/Climate regulate systems are an extremely sophisticated, lock use lots of temperature sensors positioned inside the car and also out. Sun fill sensors, fueled and also electric pre-heaters, air air conditioning system, a battery of mix doors to straight air v a maze of ducting to where it’s needed, fast. And of course, a HVAC controller (computer) to regulate it all.


Some top-of-the-range cars have actually HVAC’s that go a lot additional – Pre-heated or cooled from her smartphone prior to your journey even begins. No scraping ice cream or cold bum’s, we’re just not living!

Common faults with modern climate systems that will reason fogging within the car, include:

Blend door faultFan motor faultSensor faults

Blend doors are motorized flaps positioned inside the heater matrix. Castle open and also close proportionally as directed by the HVAC controller. The mix doors straight air to various zones in the heating system.


They’re very an accurate in your movement and the controller must understand the specific door position. A faulty mix door motor is common and also will need replacing. Controller losing blend door place is typical too and simply needs calibration.

However, you might need a dealer-level computer system to instigate the re-learn procedure. A code reader is beneficial for reading faults, but a straightforward handheld fault code reader won’t check out a HVAC controller, you’ll require a reader with better functionality.

I provided the scan device I use to fault find, actuate motors for testing and also calibrating the HVAC system. You can inspect it out below on the Auto electrical repair tools page. Faulty or lose of mix door position will reason fogging also with the warmth on.


A pan motor (aka blower) fault is additionally common, the motor may fail totally or probably the fan rate resistor. If you have actually a fan fault, it should be pretty apparent as the pan is pretty noisy.

It’s also possible for the fan rate control button on the central heater manage panel to fail. Ideal diagnosis is important, as fitting part HVAC parts have the right to be expensive and an extremely time-consuming. A an excellent fault code reader will likewise have live data readings, and motor activation functionality.

Air-Conditioning Fault

Your air conditioning is very important in the fight versus foggy windows. Appears crazy to rotate on the A/C when the warm is on, many would think that counterproductive. Yes and no, her heater’s warm air will conveniently outgun the cold.

We’re interested in the A/C’s other good strength, its ability to dried air. It removes moisture native the car interior and as friend know, that’s what reasons the foggy glass in the first place.

Without a work air-con system, your windows will certainly be challenging to clear even with the warm on and also especially in damp conditions. The A/C device is managed by the A/C regulate module (computer) and also will register any type of faults detected.

Common A/C mechanism faults include:

Low refrigerantCooling fan faultRefrigerant leakCompressor Fault

Low refrigerant will certainly be recognize by a pressure sensor and the system will be shut down by the A/C controller (computer). Low refrigerant is likely resulted in by a very tiny gas leak. A technician will height up the system, check for leaks, making use of leak detecting dye and also black light.

A cooling fan is potentially a significant fault. Not only will the A/C not work, but your engine will overheat in web traffic which could blow the head-gasket. A big refrigerant leak is commonly caused by a hole in the condenser, water tap pump seals, or Schrader valves. A dye and also black light test will certainly be needed.

A compressor fault may be brought about by an electric fault or a mechanical failure. A compressor clutch is a common failure, the clutch is turned on and also off, supplying drive strength to the compressor.

The an enig Hack


This is an anti-fog hack that in reality works, however, don’t usage this on the windshield because it may cause glare as soon as night driving. Yet it’ll work great on all other glass.

Using some shaving foam (not gel) and a kitchen towel, obstacle the within of the glass and buff that off. This applies a detergent coating to the glass and also reduces surface tension. That allows the condensation to flatten out, make it easier to view through.

So the moisture is still on the glass, it’s just more transparent. Space you sleep yet? Anyway, that works, but you’ll need to reapply every month or so.

See more: Distance From Gatlinburg, Tn To Rock Hill Sc To Gatlinburg Tn Is


Related Questions

Car windows fog up as soon as parked? To avoid fogging as soon as parked, try the following:

Park in a garage if possibleOpen interior air ventsTurn turn off air re-circulationCheck tribe vents operationOpen windows just a crack, if possible

You can inspect out all the devices I supplied in this repair including wiring diagrams and also workshop repair manuals below on the Auto electrical repair devices page.