I'm not quite sure why, but my defroster takes for f****n ever to defrost just my front windshield.

Is there any way to fix or "upgrade" the front defrosters.

Is it a temperature problem?or is there physically not much air moving?

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Generally speaking, if your front windows fog up, its actually the cars AC that kicks on to un fog the front windshield. It automatically comes on when you set the blower to the window. So maybe your ac is not working?

Bad AC could be a possibility.

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Not in my Celica. The AC button needs to be depressed manually for the AC to kick in while the front defogger is on.

That said, I almost never use it with the AC, at least in the winter. I just leave the temp to max-heat and set it to high. Defogs my windshield well.

As for the summer, if it's fogging up, then you probably will want to set it to vent, cool and A/C to get rid of moisture.

This post has been edited by solidxsnake: Dec 10, 2009 - 12:12 AM

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^solidsnake has the right idea. depending on the outside temp you will need to either us the a/c to blow cool or hot air.

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ACTUALLY... they are both right... there were two variations of the climate control put out... the blue back variation automatically puts a/c on when the defrost button is pushed... you have NO choice... the white plug variation allowed the user to choose heat or a/c... also there were two rear defroster variations put out... the one with the blue main unit left the button pushed in when it was pushed... the other (white main) was a switch that returned to its original position when pushed

as for the heat issue... if you want to use heat to defrost your front windshield... your temp gauge must be halfway or higher between C and H on the gauge (instrument cluster).... AND you should have it just on DEFROST ONLY and RECIRC... recirc will give you the highest fan rate... if its not all three of these conditions... you will have a hell of a time defrosting

This post has been edited by pittfirefighter: Dec 10, 2009 - 9:54 AM

IS THERE ANY CHANCE THAT YOUR WINDSHIELD IS A LITTLE GREASY. SOMETIMES QUEMICALS USED TO CLEAN YOUR WINDOWS LEAVE A RESIDUE AND MAKE IT HARDER TO DEFFOG.

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Try to take off the caps and what the hell is "QUEMICALS" ???
It won't affect the defrosting. With my car when it's cold and windows get fogged I turn on the heat and set it to full window defrost and works. With my wife's 96 ST she uses the A/C for defrosting year around. Only in the winter we adjust the climate to be more warm than cold. Does it have something to do with the chemical in the A/C? I don't think they use freon after a certain year yes? no?

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LMAO...
no its true... if theres residue on your window... it can make it tougher to change the temp of the windshield (this is what defrosting does)... for instance.. smoking in a car can make it a pain to defrost... the smoke residue will build up and change the specific heat of the glass... which means its harder to make the glass warm and get rid of the frost (water vapor buildup)

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A/C is called air conditioning for a reason. The freon (or whatever the coolant is) is never exposed to the air outside of the A/C system (condenser, lines, compressor, etc). The air is cooled/dried via forced convection through the system's heat exchanger (the big radiator-like object... I feel like that is called the condenser but am not sure).

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close but no.... the air that is exposed to the interior of the car never makes it to the engine bay... the freon is pushed through the compressor where it is pressurized... this pressure causes the freon to become colder when entering condensor due to noble gas laws... pressure goes down, volume up, temp goes down (anyone that plays paintball knows this from CO2 canisters... they become freezing cold when filled, the gas is rapidly let out to fill it)... this is pumped into the cabin where the heat exchanger is... air runs by the exchanger and through convection becomes colder (heat will go to the colder region, heat leaves the air and goes to the freon).... the now warmer air returns to the engine bay to go through the cycle again...
the part you are thinking of is inside the car underneath the dash... thats why there is a water outlet inside the car (it comes from inside the cabin) cause it gets really cold and condensation forms and has to be let out... (the water that drips from underneath the car when the A/C is running)

its like a window air conditioner... the air in the cabin is never exposed to the cooling element itself... just a cold area that in return cools the air

This post has been edited by pittfirefighter: Dec 14, 2009 - 1:11 AM

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Semantics, but PV/T = P'V'/T' begs to differ The coolant in the system cools when it expands in the condenser. Pressurizing the gas in the system is done by mechanical means, by doing work to the gas (compressing it, ie lowering volume). As the gas is compressed, both its pressure and its temperature rise. As the gas is pushed through the lines into the condenser, it keeps its high temperature and pressure. When it enters the condenser, however, it rapidly expands (adiabatic expansion) and drops in temperature and pressure drastically and turns into a liquid. It then cycles back into the compressor, which turns the liquid back into a gas through pressurization, etc. Hence, phase change system, uses the energy requirements of a phase change to alter temperature.

wow, I've got more info from this thread than I originally wanted to know.

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lol I just saw this thread and saw some interesting points being made...

but the answer to Matt's question, albeit no longer relevant, because he DITCHED the 6gc is that the a/c must be on with either of the two defrost selectors, and the air must be set to NOT pull air in from the outside.

The reason this is the correct answer in this particular case is because in the Pacific NW where we get absurd amounts of rain, the air just has way too much moisture in it to be able to defog the windows w/out the a/c. Believe me, I've tried, I've experimented, I've taken note. On the rare occasion that we have these crazy dry cold spells, you can totally defog w/out the a/c and just the heat, and if you give it a few minutes to circulate the moisture out of the ducts, you can pull in the air from outside, too if you want. But when it's 40 degrees and raining, has rained or is about to rain (so basically for 8 months out of the year here) you've gotta have that a/c runnin. Sucks.

Edit: this also does NOT pertain to every single car out there, but I have found that it tends to pertain more to older model cars than newer models, like 2000+. I guess it has something to do with how the air is vented? IDK

This post has been edited by GriffGirl: Jan 7, 2010 - 8:06 PM

when it happens to have way too much fog inside the window, u can either try to use some soap water to clean on it(dont wash off all the soap), or u should open some window in a day of good weather, because it might be too much water inside your car, or last one, someone told me but i never tried...use some newspaper to wipe the inside part of your windshield.