2nd Gen Non-Engine/Transmission Windows fogging up

[chopperman]

Greetings, I'm having an issue with all my windows fogging up. I have plenty of heat, no smell of antifreeze and no loss of coolant. I have not noticed any leaks from the outside, no wet floors or any thing like that. I'm at my wits end. I thought it might be my third brake light leaking, I will check tomorrow. However I'm not having any wet floors or musty smells. Floor is dry as a bone. I'm trying to figure out why my windows are fogging up all the time. My defrost works fine, it blows warm air on the windshield and the comfort selector works fine. The only thing I can think of is Heater core leaking, but it's not showing typical signs of failure, or the third brake light leaking. I would welcome all ideas I'm tired of driving with windows cracked and not being able to see. Thanks, Brian

 

[B.G. Smith]

The AC cmpressor is supposed to run when in the defrost position to de-humidify the air. May be out of comission??? bg

 

[SRath]

The dry as a bone carpet is good. As is the no coolant loss or smell. My truck gets like that when I plow, but it is strictly due to a combination of copious amounts of snow on me and my boots, coveralls, and husky mats and the evaporation of same from the heat of the cab and my own exertions (sweating) combined with the heavy breathing that accompanies same. Plowing snow with a manual trans is indeed hard physical work. Especially when you continue to invent new and better ways of getting stuck and having to get out and shovel like a mad man.

The only solution I have ever found is to leave a window down a crack. I actually have a sunroof which, open just a notch, and ice and snow buildup permitting, works very well for sucking air and smoke out of the cab without causing a cold draft. The heater is still more than ample and the air circulates better. Better yet, it tends to blow across the windows and windshield.

Which brings up another potential cause: If you have ice and snow packed over the cowl, as is common in such weather, your system can only recirculate the much more humid air from the cab. The degree of humidity is not as important as the difference between it and the extremely cold and dry air on the outside of the windows. Guaranteed to fog windows.

Finally, try turning your stereo off. All that loud singing while you're alone in the privacy of your truck is worse than 4 kids babbling incessantly at fogging windows.

 

[fest3er]

Get a room! Oh, wait. That's probably not the problem.

Check your recirc door. If it's on recirc, moisture will just build up unless the A/C is running well enough to dry the air.

 

[PBJ2500CTD]

The AC may require servicing as BG mentioned. Also, if this is occurring at low temps, below 38* to 40*, the AC may be disabled due to the low temp.

 

[SRath]

Bruce is right about things that rely on compressed gases not working well in extreme cold. Often, when trying to de-ice frozen semi trailer brakes in very cold sub zero conditions, I use a propane torch. If it is really cold, the compressed propane liquid will stop vaporizing enough to maintain a flame and I will have to warm the bottle in the truck repeatedly.

 

[chopperman]

Thanks guys I'll check the recirc. door. It is occuring at low temps. I'm sure the A/C is not coming on due to the cold temps, locally it's around 5 above in Indianapolis tonight, however on my to work tonight I noticed it doesn't fog up until the truck is warm inside. ?? almost like there is moisture from somewhere. As stated before the carpets are all bone dry and no coolant loss. I will keep checking, one thing at a time. I'm not ready to tear out the dash just yet. It's way to cold ourt and I don't have a heated shop and not really excited to give a shop $700. 00+ to do it for me. Just very frustrating that I can't figure it out. I'll keep you all posted and thanks for the repiles. Brian

 

[PBJ2500CTD]

Gee, sounds like the same thing that happens on a good night at the drive-in theater. You'd be amazed at how much humidity just your breathing will put into the air. Do you take a shower before heading to work. That'll add a bunch more.
Add together cold windows with warm, humid interior air and no AC to dehumidify, you'll experience fogging of the windows. You can crack open a couple of windows to minimize the fogging. It should clear up after ten miles of warm driving on defrost or blend (defrost/floor) mode.