Thread: humming noise

hi all, wondering if someone could tell me if this is normal on a audi a3 2.0tdi 2004,
when i have the climate control on, really low setting i hear a humming noise when the car is idle, if a rev it a little it goes away,
just wondering if this is normal, maybe the noise is still there if the setting is on full but you cant hear it i guess with the all that air its pushing out,
the heat/cold air everything seems ok,
whats your thoughts?

i just had my aircon regassed and i have the same problem.

only when i turn off the econ button the humming starts.

shall i be worried and called the compnay up who regassed the system?

It all depends on where the humming comes from. With the air con on there is an extra fan running and a belt driving a compressor, they're sources of noise of course. You'd be better off asking people who have cars of the same age and type in the relevant forums.