My mom has a '99 Accord. The inside of the windshield is getting a "haze" on it that windex won't clean off. Using stronger cleaners, it comes off, but is soon dirty again. One dealer tried to clean it with windex and a razor blade. He said he thinks it is a HVAC issue.

Can you further enlighten me on this problem?

 

could be coolant. Have you check the coolant level?

 

I had a similar problem. I could never get rid of it. I ended up replacing the windshield because of a crack and since the new windshield it hasn't come back.

 

Might help to change the cabin air filters. I'm not saying dirty/clogged filters would normally lead to that problem, but it couldn't hurt to change them. If they've never been changed before, you'll likely be shocked at how much crap they've collected.

Also, if you use an air-freshener in the car, best to use a solid type. Avoid the liquid ones which are oil-based and might makes things worse (plus aren't good for interior materials).

 

Check to see if the Recirc button is pressed, if it is, turn OFF Recirc. Also, clean in the windshield, inside and out, with a window cleaner first and then use some rubbing alcohol to rub the entire windshield down. That windshield should be sparkling clean afterwards.

If the person is a smoker and tends to keep the widows closed, that possibly could be the issue.