What the fog!!!!!!

[acon40]

Why the hell is my truck fogging up so bad? It seem the defrost will help keep it clear somewhat, but the truck fogs up so bad. My rear window needs to be swapped out s I know this is a must. But when its cold it fogs up SO BAD> anything I am missing. Its a 95 fj80.

 

[Uncle Ben]

Does it smell like antifreeze? Is the AC coming on in defrost? (it should be)

 

[Rezarf]

Wet floors can cause this too. Lots of water on your floor seem to aid in the steaming process.

Drew

 

[Man Jerk]

Do you have it sent on outside air or recirculate? Recirculating the air will cause bad fog as well.

 

[acon40]

No wet at all. I will keep an eye on the ac. if that does not click on when I hit defrost whats the deal?

 

[acon40]

Oh an Ive nothing outside helps.....somewhat

 

[nakman]

How many dogs are in the truck?

 

[Uncle Ben]

Often if a heater fogs the windows it is due to a heater core leak. I haven't done one on an 80 but I'm guessing it isn't too bad....but then again.... A/C comes on with defrost to dehumidify. If it isn't coming on does it work normally?

 

[subzali]

Oh an Ive nothing outside helps.....somewhat

Not sure what this means, but easiest thing like Man Jerk said - check to see if somehow the air is getting bumped to recirculate - I almost never have mine on recirc (only through tunnels and very little else).

 

[60wag]

Are you sure the rear carpet is dry? I had some fogging issues that turned out to be a tiny leak through the window trim mounting clips in the back near the gas filler pipe.

 

[Romer]

This is common in an 80 based on threads on Mud.

This happens with my truuck as well.

My windows always fog when the air is set to recirculate rather than outside when its cold.

A quick way to defog is turn on the AC. This does not mean cold air. Have the temp up high and turn on the AC button. This will quickly add moisture to the air while still blowing warmer air.

 

[Uncle Ben]

Not sure what this means, but easiest thing like Man Jerk said - check to see if somehow the air is getting bumped to recirculate - I almost never have mine on recirc (only through tunnels and very little else).

On an A/C equipped vehicle it needs to be on recirc on defrost as the purpose of A/C in a defroster circuit is dehumidification of the interior not the outside air!

 

[Shark Bait]

Coming home from a scuba diving trip this past January, it was really cold outside and we had the rear of the 80 full of wet gear. I had the system on recirculate cause I figured we'd get more heat. The windows kept icing up from the inside!! It was a constant battle with the scraper. Took a while to figure out we were better off pulling in outside air. We laughed pretty hard.

 

[Romer]

On an A/C equipped vehicle it needs to be on recirc on defrost as the purpose of A/C in a defroster circuit is dehumidification of the interior not the outside air!

Doing this always fogs my windows, I go to outside air and it does not

 

[Uncle Ben]

Doing this always fogs my windows, I go to outside air and it does not

Interesting! I go out and start the truck, push the defrost button (which by default activates A/C and recirc) and in >10 minutes my windows are clear.

 

[Romer]

Interesting! I go out and start the truck, push the defrost button (which by default activates A/C and recirc) and in >10 minutes my windows are clear.

That's probably the difference. Your AC activates when you turn on defrost, mine currently does not. I mentioned above that's one way to get rid of the fog. Does your setup have the Auto feature and is it enabled? Auto being you set the temp and function and it sets the fan speed and other stuff.

 

[Uncle Ben]

That's probably the difference. Your AC activates when you turn on defrost, mine currently does not. I mentioned above that's one way to get rid of the fog. Does your setup have the Auto feature and is it enabled? Auto being you set the temp and function and it sets the fan speed and other stuff.

Yesir....Climate control like yours with a new sensor and the sensor tube is attached.

 

[Rezarf]

I have an Absorber towel in my 40 for when my windows fog up. It works really well Sometimes I keep a plastic scraper handy for those really icy days.

Drew

 

[Romer]

Yesir....Climate control like yours with a new sensor and the sensor tube is attached.

I turned the auto feature off because it blew too hard in the summer. I like to adjust it myself. using the outside air works the majority of the time and when it doesn't I just turn on the AC like I mentioned above.

Now the majority of 80's don't have that feature if I recall and they would not have the AC auto engage when you turn on the Defrost, is that true? Someone with a non collectors 80 care to comment.

When I go home I will engage the auto feature and then turn on the Defrost and see what happens. I expect it will operate like yours.

 

[subzali]

UB - I've been thinking about that for a little while now. Doesn't the air just get passed over a coil to heat it up for the defroster? Heating air ALWAYS dehumidifies it, and cooling air ALWAYS increases the density which increases the humidity - thus you see water dripping from air conditioners because they are condensing and removing that extra humidity. I need to look at why the refrigerant operating (A/C on)(normally used to cool the air) would help dehumidify when the heat is cranked up when it normally increases the humidity when it's being used to cool the air...