Humid air causing fogging on all glass surfaces?

[Redheadmurray]

Turns out the entire HVAC system needs to be replaced because of some faulty valve causing the problem.

Would you mind which service center you used? I would like to have my service center contact them to save them time and aggravation.

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[Bruce in Seattle]

I have the same problem in my R1T N01790X delivered March 2023. Now that colder weather is upon us the moist air and foggy inside windshield has become an irritation for me again so I searched the forums thinking, "This cannot be a general problem for all Rivians otherwise everybody would be up in arms about the danger.".

Turns out the entire HVAC system needs to be replaced because of some faulty valve causing the problem.

I have the same problem in my R1T N0179XX delivered March 2023. Now that colder weather is upon us the moist air and foggy inside windshield has become an irritation for me again so I searched the forums thinking, "This cannot be a general problem for all Rivians otherwise everybody would be up in arms about the danger.".

I'm going to contact Rivian about it. I ask as well, @xyskis , could you provide info about the service center and maybe a contact person? I don't want to get a runaround. Also, I'm wondering if a series of Rivians had the same mfg defect... for others with the problem, are you in the same range and timeframe as mine?

 

[Riviot]

Turns out the entire HVAC system needs to be replaced because of some faulty valve causing the problem.

Can you post the work order / service item details?

 

[Riviot]

Well serves me right for commenting here...

It was a normal drive in a warmed up truck for 25 minutes, 42°F outside with damp roads, no fog, 73°F with heat on lowest fan, side vents, floor vents, dash. Suddenly started blowing cold air out of the dash only and fogged me up.

I'm pretty sure one of the last couple updates messed with HVAC settings and made it worse, all around.

 

[Antonio]

I’ve noticed this on my wife’s R1s. It just started about a month ago or so.

 

[ads75]

My windshield has started fogging more the last few weeks or month or so, mostly on the windshield. I don't remember it doing it this much last year, or in other vehicles I've owned. I'm in Pennsylvania. But my fogging doesn't look near as bad as OPs, but I do need to use the DEFOG on the ventilation a couple times to and from work in the morning and evening. I'm not sure if it's seasonal, due to an update, or something else.

 

[R1Tom]

This has to be something they messed up with an update. Mine never did this in past 2 years and now is doing it too. Hope they fix in an update....

 

[xyskis]

Mine had been doing it intermittently for the last 6-10 months but really noticeable since the weather turned. I was at the Portland service center. They replaced the inside of components of the HVAC and now the issue the issue has been resolved. So stoked to not have instafog with the HVAC, partially while driving in inclement weather.

 

[UnsungZero_OldTimeAdMan]

Cold air has more capacity to hold moisture than hot air. AC on work better to defog than heat on—to pull moisture from glass into air. This is not car dependent. It’s universal on this planet.

 

[xyskis]

Cold air has more capacity to hold moisture than hot air. AC on work better to defog than heat on—to pull moisture from glass into air. This is not car dependent. It’s universal on this planet.

Yeah, as a recovering chemical engineer, I get this. Sounds like there was some kind of valve problem preventing dehumidification. It was like hot swamp air was being blown in our faces most recently.

 

[kozak79]

I had this issue, used RainX glass treatment with this tool:

Worked like a charm. Make sure to buff it with a microfiber cloth after.

 

[Paul Hackett]

Faulty HVAC. This was a very common issue in just about all cars prior to the 1980's when the HVAC tech got much more advanced. In modern vehicles it tends to be the evaporator system associated with the HVAC. You really should not have to run the HVAC to deal with fogged windows in almost all weather conditions but the description of this persistent issue points to HVAC system leak.

 

[Paul Hackett]

Cold air has more capacity to hold moisture than hot air. AC on work better to defog than heat on—to pull moisture from glass into air. This is not car dependent. It’s universal on this planet.

Cold air has less capacity to hold moisture than warmer air.

 

[Paul Hackett]

For best results, recirc should be on so that it's drying the same cabin air repeatedly. One thought - check under your floor mats for wet carpet. There have been reports of AC system leaks where the condensate drips back in the vehicle saturating the carpet. If that happens, it's never removing moisture. Look for condensate, or lack thereof, dripping outside the car to help diagnose the issue.

All things being equal if you recirculate the cabin air with a faulty evaporator, which this sounds like, you'll promote the problem.

 

[Redheadmurray]

My R1S just got out of service. They claimed that the AC gas overcharged charged at the factory and this is causing the problem. I haven’t had conditions that would fog up the window since so I’m not sure if this solution works. Was repaired in Menomonee Falls, Wisconsin.

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