Condensation on Inside of Windshield

This time of year when the weather is right, the inside of my windshield becomes so wet that it takes a squeegee to get rid of it. The defroster will take a good 15 minutes to dry it out, hence the squeegee. This is a 2011 Access Cab that I bought brand new. This just started towards the end of winter last year. What causes this and how to I stop it?

 

When was your cab air filter last replaced?

Does the A/C work normally when the weather us warmer?

Any water leaks into the cab that are getting the carpet damp?

 

Cab air filter? Never heard of such a thing. What is it and where is it?

A/C works normally.

No water leaks at all, tho I just remembered that sometimes when I pull the seat belt out, the part of the belt that is inside the door is wet. Nothing on the inside of the door inside the cab is wet and there is no leaks inside the cab.

 

Does your AC work well?
The AC is used when the defrost is on, this is what pull the humidity from inside the cabin. Which in turn “drys” the windshield.

 

Cabin air filter is behind the glovebox, just drop it down and theres a rectangular cover the filter is behind that.

 

You access the compartment from the glove box. If you're not aware of it, it most likely needs to be replaced and could be restricting air flow.

 

Worst case scenario: heater core is leaking razing the humidity level in your truck

 

https://youtu.be/Hbm7E_MpgPc

 

Do you have the "Recirculate" button pushed?

 

Don't run it on recirculate when it colder outside than you want it inside. The human body puts off a lot of moisture. In the summer, you can run it on recirculate because the evaporator coil in your dash is colder than the dew point temperature in your cab, so it will cause the moisture in the air to condense, drip off and run out the drain hose in the firewall.
Always have it on the fresh air setting in cooler weather.

 

Your seatbelt shouldn’t be wet. There’s a leak. Water will run down behind the trim under the carpet and raise the humidity in the truck.

 

Thanks for the video. I looked at the glove box before you posted the video, and without the video, I would not have had a clue as to how to remove the glove box.

 

I never use the recirculate button. Never gets that hot around here in the summer.

 

^^^^ This. OP it’s good to replace your cabin filter yearly, but you have a door seal or some other leak if your seat belt is wet, chase that problem down.

 

Yes, that one confuses me. The inside of the door is dry and the floor is dry. Right now the seat belt is dry, but it hasn’t rained since I drove it last, so it’s had a chance to dry out, but the inside of the windshield is sopping wet. All the carpet in the entire vehicle is dry.

 

That’s the only potential place there is any leak. I don’t know why that filter would have anything to do with it, but I will replace it.

 

Pop up the door sill plastic. It lifts off. Then slide your hand under the carpet to see if it’s damp.

 

If Oregon is as humid as GA then this isn't unusual.

 

While and after it rains give your truck a good look over for weather seals leakage (like mentioned above). You may want to check your drain plug for AC/Climate control. Drain is under your truck passenger side. Possible that system isn't draining away moisture and when you run your heat it evaporates. If it's your heater core (mentioned above) there will be a smell of coolant when running your system.

 

Finally got a break in the weather. I popped the door sill off and everything is bone dry under there. It does look like there might be some moisture getting in behind the seal on the top part of the rear door. Don’t know how to stop that one. From the way it is installed, it gets compressed when the door is closed so I don’t know how water is getting in. I had to order a new cabin air filter. Should be in tomorrow.

We’ve had heavy rain for days and it only let up this morning and the part of the seat belt that is stored inside the rear door is bone dry.

I think I found a photo of the AC Drain Plug thru Google. Looks like it has ridges for using your fingers to unscrew it. Does that sound right?

No smells when using the heater.