My 06 Monte Carlo just started having this issue. No matter what position i have the dial to direct the air it will not blow on the windshield. Even during remote start.
I recently had the right side blend actuator replaced, could this have something to do with it?
Is there a fuse?

 

I would say it definitely could be the problem... IF, The defrosters worked before the blend door repair/replacement was done.

 

Yes it definitely worked before that and after. I would say it stopped working within the last week. The actuator was replaced back in October.

 

Update:
I unplugged the battery and that must have rest something. It is working fine now.

Also got my Rear defroster working. It was that damn connector under the fuse box on the passenger side.