You are correct, there is something different. GM changed the manufacturing process for the 2018+ model years. There was a foam gasket on the blend door that was implemented on the 2016-2017 models. The gasket was to prevent a flutter noise caused by the blend door chattering with fan set to higher levels. The gasket would not allow the blend door to completely seal the duct opening, so air was allowed to leak by and reach the windshield. This is not good in humid climates because some of the cold air, which was supposed to be directed only to dash and/or floor vents when not in defrost mode, leaks by the blend door and cools the windshield near the defrost vents. Cold windshield in contact with warm humid outside air causes the moisture to condensate on the "outside" of the windshield. So you have to use your wipers to correct.

2018+ models, GM removed the gasket and reprogrammed the blend door actuators to close firmly. I'm guessing by maybe increasing the shut-off current limit monitored by the CANBus?? Regardless, the doors now shut completely and there is only a very minute amount of air that can squeeze past the blend door. So now, the issue is still present, however it has been greatly minimized to the point where it only makes two little quarter to golfball sized condensation spots, one near each end of the defrost vent.

I believe that 2016 - 2017 model years need to have the windshield removed in order to get to the gasket for removal and then a reprogram/re calibration of the blend door actuator control signal. OR....you can buy a small foam pad and cut it to fit over the majority of the defrost vent (like mentioned in these discussions), and eliminate the issue. If I had a 2016-2017 with this issue, I would go the foam pad route!


Just a helpful tip for anyone reading this that thinks they have this issue, keep in mind that this issue causes fogging on the "outside" of the windshield...not the "inside". If you're experiencing this on the inside... then you either don't have your defrost controls set correctly for the ambient conditions...or you need to clean the film and residue from the inside of your windshield:thumb:

A few people who had the foam removed have stated that the process didn't solve the problem.

Ooh, that’s disappointing. That just reinforces the choice to use a dash-pad, rather than allow the dealership to remove the windshield and potentially mess something up. So far, everyone I know, including myself, who has a 2018, does not have this issue.

My 2018 does it .. I keep shop rags with me at all times to cover the vents when it acts up ..:thumbdown:

Sorry to hear that:sorry: I wonder if GM didn’t make the correction in the manufacturing process until later in the 2018 model year builds?

Mine was built November 2017 and it does not have this issue. The others I know that have 2018s also do not have this issue. Their build dates are the same or later than mine.

Mine has a June 2018 build date , I picked it up on July 19th ( my birthday ).. It's only a big deal when racing at the track ..One time about at the end of the track it got so bad I had to grab my rags and wipe the window so I would not hit the wall and find to turn off .. Bit scary when it happens ..:frusty:

My 2018 with a 5/18 build date also has this issue, and I highly doubt there has yet to be a fix. In a humid climate my guess is every Gen6 Camaro will have this problem. Kinda sad and definitely not safe....

Never had this problem with my 2010 or 2013

I live in Houston. My brother-in-law lives in New Orleans. Can’t get more humid than that. Neither of ours have this issue. Both of us have ZL1, however I don’t think that has any bearing on the issue.

Problem started in 2016.

Nope, my 2010 2SS had the issue...the amount of fogging was just not as severe.

That is odd that you say that. I had a 2011 and I never had the issue, and I never had the issue on any other car I ever had.