Frosted Rear windows

I'd been dealing with fogging inside due to all the moisture of melted snow from our boots. I put in a tub of Damprid inside the cab for a few days and it fixed the issue.

 

Is not fog it's ice!
I wish I could move south!

 

pro tip. A/C is never gonna come on below 30F. To keep evaporator from freezing. when set on defrost system defaults to sucking in fresh air/dry winter air.

 

I get the same issue when it's really cold out. Although to be fair it happens in all my vehicles when they get left outside in -35 and then you start them up and start driving, I guess you can only do so much to relieve the moisture in the air when it's that cold. Wish I lived somewhere warm when it gets really cold out here.

 

It actually is a fog. When there is a high moisture level in the air, it condenses on the cold windows, since the windows are below freezing, the fog freezes to the window. A anti fogging spray could actually prevent it from condensing on the windows so much.

Ive spent 36 years in MN, if you want to get rid of this as a issue, then you need to get rid of the moisture inside the air in the truck. Putting the window down when its below zero will exchange the warm damp air out for cold dry air. But you need to figure out where the moisture is coming from. Sometimes its just from kids breathing so much in the back seat, sometimes its from snow melt on the floors, sometimes there is a water leak.



Think back to when you were a kid, did the bus windows fog over in the cold? how did the bus driver stop his windshield from fogging over? They have fans that blow air at the windows to dry the moisture before it can freeze. The back seat or your truck has no air flow over the windows, so the windows fog up and freeze.

 

Open 2 windows (for cross ventilation) a half inch or so while you are driving. That will help the HVAC system remove some of the xtra moisture . Also make sure you do not have the Re-circulation button on.

 

OP.....it is ice that has formed on the cold window from the humidity in the cabin air.

Suggest the following steps:
1. open the rear most windows about 1/2". If the yard apes complain, close the windows and let them know they won't be able to see out.
2. when the defroster has cleared the windshield, shift the air to the dash vents.
3. Aim the 2 most outboard (closest to the driver and front passenger) doors to blow on the windows. The air will make its way to the open windows.
4. set the fan on HIGH and maximum temperature
5. Be patient. Drive. It will take a bit of time for the windows to clear.
6. clear any standing water on the floor mats (front and rear)

These simple actions will help to "dry" the air, place warm air along the windows and give a place to vent the "wet"/humid air.

Humans exhale a large amount of water vapor. This vapor will condense/freeze on cold surfaces. It is nature.

 

and if you have water from the 3rd brake light getting inside the frames on the doors, then you have bigger issues...lol