Decided to post on the Tech Thread as well as the General Discssion since this is a technical issue that has been unresolved and affects a number of C7 Vette's. No big deal but a recent post caused me to possibly understand why my Vette closes with surprising little force from a high or low opening with the door open and will not latch with it closed.
First, I have been at this hatch issue for 9 months. I have to open my door to have the hatch latch. A number of others have posted the same result. I have tried many things such as checking to be sure my memory wire vent works-it does; adjusted the hatch stops to a point where the perfectly fitting hatch is raised and lowered so it doesn’t fit-no help. I have tried with various force levels from high and low openings-no help! Watched the video which a dealer salesman made (on a car obviously that does not have a problem, which many also report and think we who don’t just don’t know what we’re doing!) – no help.
I have also been wondering for 9 months why mine closes with surprising very little force from high or low positions with the door open. The following is a possible solution. Here are two forum posts:
First Poster (with possible explanation of the issue)
“I was setting in the car with the windows up and my wife was putting stuff in the trunk and shut the hatch hard, and it like to have busted my ear drums from the pressure.” Just think if you close the trunk lid to hard with the car sealed up ,it could bust the speakers do to the over pressurizing in the compartment!
If I don't change my mind, I’m thinking of getting a powered hatch latch that will pull the lid down. and modify it to work on the C7.
Second Poster (who validates sealing as a possible cause)
Years ago, this problem never existed with any of the vehicles built here in the U.S. of A. I first discovered this phenomenon of air pressure causing doors or in this case rear hatches to close with more difficulty with Japanese imports. It didn't take me long to realize the weather stripping and seals in the imports were actually doing what they were supposed to be doing and that was to seal up the interior of the car. It also didn't take me that long to perhaps crack a window open enough to eliminate the resistance in closing doors or in this case hatch lids. This problem is not really a problem at all, but a sign that the American Automakers are actually building a much higher quality vehicle with all the weather stripping and door seals doing exactly what they are designed to do, seal the interior.

Speculation Why Some Cars Are Better Than Others and the Thought That the Seal Breaks in with Time:
Folks who have had problems and it gets better with time have suggested the seal gets softer. Perhaps that is the case but my seal feels very soft! Here is another possibility, some cars are tighter than others! Obviously the fellow who’s ears were pressurized had a tight car! Maybe the Vette gets less air tight with miles!
GM probably knows the answer and perhaps will build in a controlled leak in the 2015! (Could be why we see nothing about this issue from the Chevy folks who monitor the Forum!) Perhaps the memory wire activated vent was tried and worked on the initial test cars because they were no built as tight! Would be interesting if someone has a quick acting pressure transducer that can measure transients on a car that has a hatch that works and one where it does not latch!

 

If GM had spent as much time figuring out how big to make the hole as they did designing the fancy-smancy system to open it, the hatch would close by dropping it from about a foot high, just like it does when the door is open.

No matter how you open the vent, if the hatch does not close with it open, then the hole is too small.

Also, unlike when the door is open, the air must be forced through the carpet and trim to the vent, which creates a restriction for air to escape.