front windshield defog problem

[lexs470]

With the snowfall today, I had the front defogger on and it just didn't seem to do it's job. the climate control works perfectly for the heat/cold mode but the defogger just won't work. the inner window was defogging, but the exterior was so cold due to lack of upward air that the wipers kept freezing and i had frozen snow all over the front windshield.
What am I doing wrong here ? can someone post some suggestions ?
thnx.

 

[jjbodean1970]

it was too frigging cold

 

[hank14]

I've had the same problem a couple of times this year. It helps keeping the A/C on to dehumidify the air, and switch the manual fan to Hi and the heat to high (obviously). My problem then is I burn up, but it will keep the windshield clear.

 

[lexs470]

Well, compared to the other cars, this is what I have noticed.
If I put the climate control on auto and the temp around 75degrees, the the fan is on low speed mode, and even when i push the front defogger button, the fan keeps itself on the low speed which is nowhere sufficient to do the defogging.
is that really normal ?

 

[jjbodean1970]

yes, because it's set to auto mode and the defog won't really kick in good until the vehicle has heated up to a certain point. keep driving long enough for the vehicle to warm up and the defrost will get going eventually.

 

[lexs470]

actually that's the thing, i had already driven about 20 miles but the defogger still wasnt kicking in, i had to manually turn the fan mode to max while the defogger button was pressed. Never had to do that in the lexus ls400, which has the same exact heating mechanism. The defogger's fan was going in high only when i either put the fan in high manually, or when i switched from auto to the defogger mode, if i turned the heat hight in the 80 degrees, that's when the defogger used to kick in.
is that normal operation ? the wipers on any other car / truck usually starts to melt the ice on them once the defogger starts to work, but in this truck none of that was happening and i was unable to drive the truck anymore because of stuck ice/frozen wipers.
any ideas why?

 

[jjbodean1970]

no ideas, maybe take to the dealer to have them check it?

 

[hank14]

Possibly a faulty a/c controller switch? I dunno- ours went out in the Avalon- had to replace the a/c computer. What year is your LX? How long have you had it? How many miles? Welcome to the board. Hopefully it's nothing major.

 

[lexs470]

I will be taking it to the dealer in the morning, however I did some more playing around with it and this is what I've noticed.
When the front windshield defogger button is pressed the only thing it does is, it directs the airflow to the windshield. However like the other lexus models, it does not turn the fan speed to full, neither does it turn the A/C on.
Is this normal for the lx470 / land cruiser models ?
More over, i drove for about an hour today and kept the defogger on with full heat and full fan, the heat was coming out from the defogger vents, but they failed to melt the ice on the windshield or the wipers...
never had this happen on any other car, not even the corolla.
is that a design fault ?

 

[Jukelemon]

On my 98 and on the 99 I use to have, when the defroster position is selected on the vent location dial, the A/C automatically comes on AND the fan automatically goes to Hi (if set for Auto). In other words, it does not wait for the heater core to warm (as if you had the vent location on Auto).

 

[hank14]

I will be taking it to the dealer in the morning, however I did some more playing around with it and this is what I've noticed.
When the front windshield defogger button is pressed the only thing it does is, it directs the airflow to the windshield. However like the other lexus models, it does not turn the fan speed to full, neither does it turn the A/C on.

My 99 doesn't havbe afront defroster button, only the two dials. When turned to defrost, the fan turns to hi and the a/c turns on, even before the engine warms up. While driving with it cold out and snowing, I was getting heavy fogging and water accumulation on the inside of the windshield with ice on the outside. The defroster could barely keep up.
More over, i drove for about an hour today and kept the defogger on with full heat and full fan, the heat was coming out from the defogger vents, but they failed to melt the ice on the windshield or the wipers...

That is what mine does, even drving on mountain trails in the snow.

never had this happen on any other car, not even the corolla.
is that a design fault ?

I think they modeled it after the Ford F-series.

 

[Jukelemon]

OK. Small change to my post. When it is cold i.e. cold start and I do what I stated above, it is true. When I went out there and tried at lunch i.e. after driving a bit, the A/C came automatically but the fan did not go to high-it stayed at the same setting as if the auto climate was in control i.e. same setting as any other vant control location.

Make sense?