01 RX300
Raining outside, and it fogs like crazy.
I have to turn on windshield defog every about minute or so. Of course, that turns on AC and takes power away from the engine
I pulled cabin air filter, it was quite dirty. I cleaned it but it did no difference.
We had a 99 RX and I do not recall it fogging so badly.
Any ideas?

 

Actually, I found a long thread on fogging yesterday here. According to it, that's how they are. Cure is to keep AC on and put it into fresh air mode. One poster says to run heat onto the windshield until it warms up and then it stops doing it.

 

I've found that a dirty windshield on the inside leads to more fogging (primarily finger prints/oils). Try giving that a try if you haven't already.

 

Certainly. I'll tell her to wash and scrape inside.

 

AC on in damp climates will wick the interior moisture out. Theory is the cool eval coil will conduce the moisture in the cabin and drip it out. If you don't then the moisture laden interior air will condense on cooler parts ... glass, metal etc and that includes switches. AC will take some energy, but overall it is better to engage it.

Salim

 

I only had excessive fogging parking back in the day. I will say it will be the sunroof channel is blocked and getting water in.

 

Dry carpets. Unless I missed it. But plausible. I'll get to it weekend.

 

Aight. But it's 172 000 miles vehicle, so it notices AC right away. And mpg is ****ty enough as is, no need to worsen it with AC when it's cold outside.

 

Don't want to belabor the issue but removing heat is one aspect of AC, the other is sucking out moisture.

You can run it for couple of minutes and also redirect the air flow, so that it does not blow air in your face. You can still turn up the heat [you will have to wait for coolant to heat up]. In auto and defrost, the vehicle is smart to up the heat and turn on ac and direct airflow. in non auto, and not defrost, the AC will be temperature based on/off. The defrost also adds electrical strain.

At the end,, it is all comfort - cost issue.

Salim