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FIX: Excessive Moisture/Condensation/Frost on Windows

76620 Views 53 Replies 24 Participants Last post by  Xnitro67
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 | | 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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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.
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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.
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The question then becomes, how could the control teach itself to command the motor with the incorrect number of pulses?
A binding mechanism, possibly due to a small twig that came in with the leaf litter. Although Rob has a good point. Not to many years ago, you knew your battery was on the way out when the radio station memories got wiped after starting the car. (Battery voltage dropped too low.)

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?
Which begs the question - why?

Do you have the "climate control" or just regular HVAC? If climate control, then it may be sensing it needs to switch modes or something since the car is now at a different temperature than when you parked it.

Reading though the manual, the number of sensors surprises me. There's a sensor to shut off fresh air if you're behind a smelly truck.
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Does pulling the fuse and making it relearn resolve this?
Should. But if there's a mechanical issue, it won't fix that.
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.
What's the alternative? If you track snow in, the same thing will happen regardless of what floor mats you have. The rubber mats just make it easier to dump the snow/water.
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.
You can try the HVAC Reset outlined in this post up thread. While that conversation was about the recirculating flappers, the process resets all flappers - including the ones that control the ducts. It's worth a shot.
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We have not had any rain for a few days, the inside of the car is dry and it is garaged over night. So now to troubleshoot why I get the condensation on the windshield like that.
Check spare tire well for water.
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