Whinning metalic noise when a/c turned on

[anxious]

I get a whinning metalic noise when a/c turned on.

I can feel it from the steering.

It not very loud but just annoying.

When I open the bonnet I cant hear the noise outside as in the cockpit.

Any suggestions?

[anxious]

actually its more like humming....any idea?

[KenC]

Are you sure it isn't just the compressor cycling?