Frozen windscreen inside the vehicle

[Debbie3606]

Has anyone experienced a problem with the inside of their windscreen freezing (T-Roc 2019). I have taken to VW who say as it’s has passed the water test it’s has no fault. My windscreen is as frozen on the inside as it is on the outside. I have also had to buy something which I have in the vehicle all the time to absorb moisture, otherwise I spend forever trying to clear the windscreen!

 

[Crasher]

Use your air con in recirculation mode, this will remove (dehumidify) the water vapour that stays in the cabin due to you and your passengers breathing.

 

[Gazwould]

That's the opposite to what I've heard .

 

[Sam&Anne]

Been using Kontrol moisture absorbing crystals in a purpose designed container trap for years on several of our cars. The trap needs to be emptied and the amount of water is often surprising.
Honda Accord albeit 18 years old was worst but now 5 year old Golf has the same issue although nowhere near as bad.

 

[Crasher]

That's the opposite to what I've heard .

Taking the air from inside the car rather from outside, then passing it through the evaporator, causes moisture to condense on the evaporator; this builds up until droplets are formed which drain down to the collector sump under the condenser. This water is then exhausted via the condensation drain pipe, not only by gravity but by the positive air pressure within the HVAC system generated by the blower fan. The now drier air is then blown back into the cabin and the process is repeated so drawing more moisture out of the interior not just from the air itself but deep down from absorbent materials by wicking.

 

[SadClouds]

This could happen if you use de-icer to clear ice on the outside. As the ice melts outside, new ice starts forming immediately on the inside. It draws the energy from glass to melt the ice outside, so much that the inside starts to freeze. Otherwise, try what Crasher suggested, remove any damp items from the car and get a frost cover for your windscreen.

 

[dj_ek]

You have a leak. I had the same issue. Ask a competent garage to strip the seats and carpets, you’ll find there’s water under there - does your car have any modifications to its rear such as towbar or rear hard-wired dash cam? That was the ultimate cause of the problem in my case.

 

[SpikyBob]

Agreed - IMO water leak somewhere - an abnormal level of moisture inside condensing on the glass and eventually freezing as the outside temperature drops. Normal conditions and operation of HVAC do not cause significant condensation overnight. If you can’t lift the carpets buy a cheap moisture tester from Amazon and prod around to find any high levels on carpets seats etc. This may allow you to find an approximate area to look for points of entry. Check visually the spare wheel well in the boot a favourite spot to gather water. Final thought - does the rear screen wash work ok? The small hose junctions from the pump under bonnet may possibly be leaking along the way - especially if left without sufficiently strong washer fluid to avoid freezing and then causing a joint to separate under pressure. Good luck!