Is this big problem? Can i remove this part from the bottom and replace it alone, or is it hard to DIY. THANK YOU

It should be a flap motor that needs replacing, the one that operates that flap.

Hi,

 

I also have a very similar problem to yours, with the flap making intermittent clicking noises when operated either via the air re circulation button or when reversing. Did you find a solution to your problem? Is it easy to access the motor and replace?

 

Come on people, these flap motors do fail a lot across all VW Group cars/ages, someone must know where the recirc flap motor resides!

 

I'd only spread gloom and doom as in my old 2000 VW Passat, that job was definitely and absolutely and any other added words, a dash out job, so it got ignored!