I have small hairline cracks in my black dash were the defroster vents are near the vin plate. I was wondering if there is any way to fill and repair them. It really irritates me when it gets warm out, because they exapnd and look horrible!
I have the same thing. doesn’t really bother me.
I HAVE THE SAME PROB… I WOULD LIKE TO KNOW A SOLUTION ALSO!
I THINK they have a vinyl and dash repair kit at the auto store for a few bucks, and you fill in and seal those small cracks.
Keep the rest of your interior Armor-All’ed ALL the time, so that they don’t crack. Because usually, when it starts, there’s no turning back, it just gets worse and worse. The places to worry about is the top of the dash (of course) and the vinyl that is directly under all the windows. And the trunk area, if you’re into detail… 
armor all is not the greatest product for protection. Armor all from what i know of is a water based product that promotes cracking. You might want to stay with an oil based product they seem to protect better.
To prevent further cracking, use a dash cleaning agent that containts sunscreen protectant such as Turtle Wax with sunscreen or 2001 - they work better than Armour All (don’t leave a sticky residue on surface) and protect your dash from further sun damage.