Hello,

I did a filter replacement following this guide on my B6 A4. I'm a completely newbie on doing this job.
Unfortunately, I noticed that the connector marked in the pic starts clicking after my replacement, with a regular frequency (about 2 clicks/sec).







Some more details:

• I did disconnect the hose on the input side of this connector while trying to open the air box lid, so I'm suspecting this might be the reason of clicks.
  
• The clicks normally don't happen until a few minutes after the engine starts.
  
• The clicks sometimes go away for a short period (like 1,2 minutes) and come back again.
  
• When I touch the connector with my hand, I can feel the click/vibration inside it.

My questions are:
What is this connector used for?

Is the connector supposed to be clicking as I experienced? (I suppose not :P)

What's the potential cause of the clicks?(so that I can fix it)

Thanks very much!