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FIX: Excessive Moisture/Condensation/Frost on Windows

86K views 53 replies 24 participants last post by  Xnitro67 
#1 · (Edited by Moderator)
For some time now there have been many Cruze owners posting about excess moisture inside their Cruze, leading to foggy or frosted up windows that compromise outward visibility. My car was no different and I assumed, as most did, that it was somehow related to the small engine not putting out a lot of heat.

A couple weeks ago my car got to the point where all four of my windows were frozen shut (from the inside!) and the rear window was frosted over so bad that even using the rear defroster wouldn't clear it. The weather was cold and humid, yes, but I hardly ever have other people in my car and started wondering about how much more ridiculous it would be if I regularly traveled with several people in the car... it does have five seats, after all.

The evening of Friday January 16th was particularly COLD out, with temps hovering around -20C (-4F) and the sky was nice and clear; relatively low humidity. I decided to take my car out for a blast on the highway, get it heated up good and hot, and see if I could clear the windows.

A half hour on the highway with the heat blasting and the rear defroster cooking away, my windows refused to thaw. This could not be normal...

Fueled by some information I'd read in Colt45's thread regarding re-circulation and humidity, as well as member Robby's observation that the re-circulation flaps can be observed operating behind the glove box, I decided to pull into a gas station and have a look. Lo and behold my re-circulation flaps were not operating properly! They were out of sync with the commands from the HVAC controls, and both the fresh air flap and re-circulation flap were closed when in the Fresh Air (FA) mode. When I switched to the re-circulation (RC) mode, the fresh air flap opened. Here's a video I shot demonstrating the condition:



What I forgot to mention in that video is that when both flaps were closed (in FA mode), the fan was fighting to draw air through whatever gaps exist between the flaps and the housing, and since the gaps are much larger on the RC flap that's where most of the air was coming from... inside the car. Once the flap orientation was corrected I experienced a HUGE increase in airflow through the vents from fan speed 2-up (my car is a '12 with the 4 speed fan control).

Here's a video demonstrating the correct operation of the flaps as well as how to get them in sync with the HVAC controls:



This is extremely easy to check. If you have moisture issues and are not able to check this yourself, please get someone to check this for you. If your car is under warranty this will be your local dealer. Here's a How-To on cabin air filter replacement for those interested in looking at this themselves:



That frigid Friday night, once I had my car operating properly and frost-free remarkably quickly, I decided to test out how well it would defrost. I drove the car with the windows down and heat off to cool the interior, then pulled into a parking lot, shut the car off and rolled up the windows, and proceeded to breathe until all the windows were frosted over completely (several minutes). I started the car and put the defroster on full hot, fan 2, and was SHOCKED at how quick it started defrosting (the engine was already warmed up). By the time I got a video rolling half the windshield was already defrosted:



I should have kept the camera a little more still, but towards the end of the video you can see the moisture coming off. The sides of the windshield don't defrost nearly as quick as the middle directly over the vent. Remember, it was really cold out when I shot this!

I also met up with a local member who was having issues with moisture in his Cruze. Member stuckoncanada has a Cruze Diesel with moisture issues, and when we had a look at his re-circulation flaps he had an issue completely different than what I did.

His car was frost-free the night we met up, and indeed his re-circ flaps were in the FA position when we had a look. His issue was with the re-circ actuator not moving the flaps far enough. The gear seen in the videos SHOULD move about 7-8 teeth when switching modes, but the gear in his car was only moving 3-4 teeth. Instead of going into RC mode it would go halfway and stop with both flaps partially open. I have to assume that something was up with his re-circulation system that was responsible for his moisture issues as well. He has since had his car fixed at the dealer (re-programmed the HVAC module) and will report back with whether his situation has improved.

So it seems there are two separate and mostly un-related issues with the Cruze, one being the well documented "slow to heat" syndrome (small/efficient engines making little waste heat), and the second being the potential to have re-circulation system issues. I have a strong feeling that there are MANY people with the second (re-circ) issue who don't realize it. I was that way, assuming based on forum talk that it was just a "characteristic" of the car, even in the summer on rainy days!

And finally the most important part. If you have moisture issues REPORT THEM! This is important even if you are able to fix the issue yourself or get it fixed at your dealer! The NHTSA can only track issues it knows about. If this is an issue with your car and it is remedied without a report, the NHTSA will have no record of it and will not track the issue, nor will they be able to warn GM of the issue's severity and or warn other owners that this issue exists and to have their car checked out if they experience these symptoms. This is a hazardous issue that can, in extreme cases, make the car unsafe to drive.

If you have moisture/condensation/frost issues with your US Cruze, please report it here:

File a Vehicle Safety Complaint | Safercar.gov | NHTSA

If you are in Canada, here is the link to the Transport Canada Defect Complaint Form:

Defect Complaint Form

Please feel free to reference this post if someone contacts you looking for further information.

There are many complaints about moisture in the Cruze on this forum. I have no idea how widespread the issue really is... there are hundreds of thousands of these cars sold every year in North America. I certainly see lots of people driving a Cruze with no condensation so this is not what I would call a common issue. I don't want to blow it out of proportion but I DO want people to be aware of the issue and also know how to go about fixing it or having it fixed.

My car is FROST-FREE now! I hope this post helps others get that way too. :)

==========

UPDATE: I forgot to mention a very basic but very important point in my thread:

You can't watch the recirculation flaps move if you're in defroster mode!

You have to have the vent selector set to anything but defroster mode to get the recirc flaps to move. The HVAC system will automatically go to the fresh air position and stay there if the defroster mode is selected, regardless of which recirc mode you've selected.
 
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#3 ·
outfreakingstanding! Question: was your car always like this (assembly issue) or did it happen somewhere along the drive time (possible design issue)? I guess I'm asking if it happened once, can it happen again?
 
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#4 ·
I guess I'm asking if it happened once, can it happen again?
My next trick will be to try and figure out how the flaps got out of sync with the HVAC controls in the first place.

My gut feeling is that it may have something to do with disconnecting the battery while the flaps are in the opposite position to where they're at during assembly? I have no idea, that's just a hunch and I'll have to experiment to see if that's the case.

It could be a defect in the HVAC module or a programming issue. I've heard several reports now where HVAC controls were replaced, modules were re-programmed, actuators and flaps were replaced... the fact that there appears to be no feedback from the actuator means that almost anything can be going on in there and neither the HVAC controls nor the driver are aware. My car displayed no signs of being "aware" of my tampering, even when moving the actuator by hand with the ignition on and the HVAC operational.

EDIT: To answer your question, I don't remember thinking one day, "Gee, there's lots of moisture in here." So I'm not sure if this was always like this or happened somewhere along the way?
 
#6 ·
I went out and checked mine just now...mine are working correctly - June 2012 cruze. I have some fogging when it's cold and rainy, but I've always been able to take care of it in at least the front windows with fan speed 3 and fan speed 4 for a few minutes on only defrost would keep the back windows clear but I can't switch it off defrost or below 3 because it'll start to fog up again. I'm going to clean the inside of my windows and see if it helps.


Sent from AutoGuide.com Free App
 
#7 ·
I have some fogging when it's cold and rainy, but I've always been able to take care of it in at least the front windows with fan speed 3 and fan speed 4 for a few minutes on only defrost would keep the back windows clear but I can't switch it off defrost or below 3 because it'll start to fog up again. I'm going to clean the inside of my windows and see if it helps.
Just to be clear, you have it set for fresh air? (Recirculate light is off) This fix just makes sure the car is doing what you tell it. You still have to run in fresh air mode to be moisture-free.
 
#8 ·
Just washed my car tonight in 30F weather and my windows all started to fog up. I crack the windows and they seem to clear up within a minute.

This time of year I regularly drive thru 0F to -15F cold weather for 45+ minutes at 55mph and my windows tend to stay clear. The exception is the driver side window begins to freeze up from the moisture I exhale. I crack a window or two and keep the heat close to max with the 3-4 fan setting and the windows stay clear.
 
#9 ·
Just verified mine has been working as it should. Still really glad to have checked, was already a dozen small leafs in the cabin filter I changed in October. Its also good to know if I ever have an excessive condensation issue, where to look for a possible cause.

Thanks again for looking into this, I'm sure you will have helped many people with this.
 
#10 ·
Just chiming in here - I never had a look myself, but the first couple months with my car the AC just sucked (was always in fresh air mode no matter what I pushed or did) and I could smell outside fumes constantly.

Probably had something similar to what is going on in Blue Angels video, but my dealership determined that the HVAC head unit was "shorted" and replaced the head unit and the system has seemingly worked pretty well since.
 
#11 ·
From reading the 2013 service manual:

The Air Recirculation Door Actuator (as well as the Air Temperature Door Actuator and the Mode Door Actuator) is a 4 phase stepper motor. I don't see any limit switch. However, from reading the text, it seems that the system does sense the range of motion end points - probably by monitoring the motor and detecting when it stalls. (There is a DTC code for stalled motor.)

While programming via a scan tool is preferred, it is possible to program it manually. This is the same for "manual" systems and "automatic" (climate control?) systems.


  • Clear all DTCs
  • Turn off car
  • Pull the HVAC control module fuse (F17 in the instrument panel)
  • Wait at least 10 seconds
  • Install fuse
  • Start car
  • Wait at least 40 seconds for self-calibration
  • If possible, check for any codes set by self-calibration failure


But we still have the question on how things get fowled up. I don't think pulling the battery would do it as it looks like it would just re-calibrate itself. Perhaps it's changing the HVAC controls before the calibration is complete. I also wonder about the possibility of leaf litter jamming the doors and giving a false range of motion. Or maybe the data gets corrupted somehow. I do find it odd that it opened the fresh air door when recirculate was commended. Unless it cycles when run past it's normal operating limits it would almost seem like the motor would have to run backwards.
 
#14 ·
From reading the 2013 service manual:
Great info! I will be picking up my 2012 manuals soon for a cross reference, but I assume they will read the same.

Stepper motor makes sense; a given number of pulses would drive the motor a given distance. The question then becomes, how could the control teach itself to command the motor with the incorrect number of pulses?

It makes sense that the system can calibrate itself also. It seems to me that sometimes when starting the car the HVAC goes through a very long process of motors buzzing and flaps moving around. Maybe it's going through a calibration process? I'll have to observe the recirc flaps in action after pulling the fuse and see what takes place.
 
#12 ·
Great post!! As I've only had my CTD back for a day now we will just have to wait to see what happens and how cold it gets here in Ottawa. My issue became very apparent with -30C temperatures.

I concur please report this condition. In researching about condensation in these forums it appears many of you have had an issue with moisture and when I took my CTD back to the dealership they told me I was the first to mention this problem (and I have water coming out of the headline due to build up!!).
 
#13 ·
Thinking about the 'Why did it happen' question.....I am tempted to speculate a relationship between the HVAC memory and that bloomin' negative cable or isolated body ground stud biz.

Manual said fuse out for ten seconds to force a re-learn.......I wonder if the momentary open ground circuit 'stuns' the HVAC module, causing it to lose orientation.....

Like I said.....just wondering if...,

Rob
 
#15 ·
I'm tickled my observations prove valuable from time to time.......Awsome post....great legwork BlueAngel.

I must apologize for failing to bring up one other tidbit that could be of value.

The discussion involved what is bringing the condensation into the car......we know that operating in recirculate, by intent or mechanical fo-pa, keeps and adds moisture.
This as well as damp floormats, winterwear etcetera, but I failed to mention one thing.

Be certain the spare tire well isn't carrying around a gallon of water from a seam or taillamp leak.
It happens often and is just as frequently overlooked.......I failed to mention it only because it was always the first place I looked when condensation was the concern.

Your heavily fogged window video started my memory juices flowing.

Rob
 
#16 ·
Be certain the spare tire well isn't carrying around a gallon of water from a seam or taillamp leak.
It happens often and is just as frequently overlooked.......I failed to mention it only because it was always the first place I looked when condensation was the concern.
I had a leaky taillight too...GALLONS of water in there/the trunk carpet...
 
#20 ·
Im going to speculate that the module got logic locked from turning the ignition off half way through the door moving or a loss of com with actuator, It probably wouldnt reset itself in these cases as it would still think its learn values were valid. Definately really weird though.
 
#22 ·
Haha... I forgot to mention a very basic but very important point in my thread:

You can't watch the recirculation flaps move if you're in defroster mode!

You have to have the vent selector set to anything but defroster mode to get the recirc flaps to move. The HVAC system will automatically go to the fresh air position and stay there if the defroster mode is selected, regardless of which recirc mode you've selected.

Will update original post. :)
 
#25 ·
Same document....simply put, if it is not due to the bled door issue, you are screwed. If it is the blend door fix that you have come up with, then the owner is fine.

This also is affecting all the TRAX suv's but not the Buick Verano. Which means that since the Buick shares the same platform as the Cruze, it all leads back to the 1.4 Liter motor. The Buick uses a much larger displacement motor and it has no issues. In fact, it has great heat. My brother has one.
 
#26 ·
This also is affecting all the TRAX suv's but not the Buick Verano. Which means that since the Buick shares the same platform as the Cruze, it all leads back to the 1.4 Liter motor. The Buick uses a much larger displacement motor and it has no issues. In fact, it has great heat. My brother has one.
I just rented a Verano for a week long training trip to Toronto. Yes, the car heats up very quick. It also burns more fuel. :)
 
#27 ·
I checked mine today. It was offset so on fresh air mode, the fresh air door was only open a few mm and the recirc door was closed. when changing modes, the fresh air door opened then closed to the same position while the recirculate door opened.

I tried the fuse reset and it was still wrong after the self-calibration so I turned the gear by hand to align the doors properly and it seems to work now, although I'll be re-checking it in a week or two to make sure it stays that way.

Seeing as how the fresh air door never opened more than a couple mm, a lot of things make a LOT of sense now. My car always smelled dusty in fresh air mode, and once the car was hot, I could never get cool air coming in from outside. I figured it was a really bad case of heatsoak, but now I see that I was never getting any notable amount of air from outside in the first place.

I went for a brief drive and everything smells so much better. Fresh air makes such a big difference.
 
#28 ·
Checked mine today, mine was just the opposite... going to recirc mode the gear doesn't move much and still stays partially open. I manually found a medium ground so both modes are acceptable but the motor doesn't seem to move the gear enough. Does pulling the fuse and making it relearn resolve this? I had the hvac unit updated last year for an unrelated problem of the sun load which there is a tsb for on bright days.
 
#30 ·
I'd also like to point out that wet floormats will have an effect. If you get in with a bunch of snow on your feet and it melts and saturates your mats, the moisture will rise and cloud up your windows and eventually freeze if it's cold enough outside. This is one reason why I don't use the rubber floormats(or weathertechs) in the winter. All that snow melts and just leaves puddles of water on your floor after you turn your car off.
 
#32 ·
Removing fuse for relearn didn't do anything, it causes fresh air to be max fresh air and recirc to be still 15% open. Still had to adjust gear manually. There's no mechanical problem it just doesn't command the gear enough
 
#36 · (Edited by Moderator)
For some time now there have been many Cruze owners posting about excess moisture inside their Cruze, leading to foggy or frosted up windows that compromise outward visibility. My car was no different and I assumed, as most did, that it was somehow related to the small engine not putting out a lot of heat.
Isn't there or shouldn't there be a TSB so that the dealer can correct this problem?

My late built Diesel has been doing this here in So Cal ever since I bought it and the dealer has no clue how to correct it!

Regards,

Derrel
 
#40 ·
Have you been able to verify the position of the flaps is correct? Check the videos I posted if you haven't already. With the cabin air filter removed the flaps are easy to see with a flashlight.

If it is extremely humid outside the only way to defrost will be to use the AC. If it's happening on days that are not really humid you likely have an issue.
 
#37 · (Edited)
I had this problem most of this past winter with my Cruze Diesel. It only appeared to happen half-way through the winter however. I'm hoping this is the issue. I'll be taking a look at it tomorrow and if the issue is present, I'll be taking it to me dealer for re-programming.

EDIT: Checked out the flaps today after work and they are moving fine. I guess it's something else...

Just to clear things up, circulating the air is what fogs up the windows, correct? Dragging the fresh air from outside (even if it's humid) will help remove the foggy windows?
 
#38 ·
Just to clear things up, circulating the air is what fogs up the windows, correct? Dragging the fresh air from outside (even if it's humid) will help remove the foggy windows?
Assuming the outside air is cold, it's not going to have much moisture. And once it warms up in the car, it will be quite dry.

But if you're talking about a day at 80F and 80% humidity, uh, no. The outside air will have a ton of moisture that will need to be wrung out of it.
 
#41 ·
I have a 2014 Chevy Cruze... just 6 months old. I am getting huge amounts of condensation on my outside windshield, just above the air vents. The opening in those dash vents blow air-conditioned cold air onto the windshield. The only way I can control it is to keep a folded up bath towel laying on top of the vents. Any other kind of towel isn't thick enough. I've been to my Chevy dealer. He said they ran some diagnostic tests that did not come up with any errors. The condensation is HUGE, and it's happening when it's humid. I've never had a car that does this. There doesn't seem to be any control whatsoever with those dash/windshield vents. No matter what direction I set the vents to (feet, upper combo of both), the same amount of air whooshes up through those vents. It's a nightmare... I already spoke to someone at Chevy Customer Care. They're the ones who set me up with today's appointment. Any suggestions?
 
#42 ·
However they designed the HVAC diverter system, it leaks a little bit of air through that windshield vent. I think they all do that, and I don't know that there is a fix. Maybe it was intentionally designed that way to keep the windshield from fogging up on the inside. It is really annoying on humid evenings though.
 
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