Vibration when I turn on the A/C

[AmigaJoe]

When I switch on the air in my '02 SE1 a sudden vibration starts that seems to resonate the cabin so my ear drums are thrumming! I remember reading about how well balanced this Ecotec engine is supposed to be. What could the issue be? Motor mounts? A/C compressor? Something else?

 

[melsg5]

If it's only with the A/C on I would guess compressor. Have you looked under the hood with the A/C on to see if the compressor is emitting the noise?

 

[AmigaJoe]

Oops...

Actually I haven't. I usually only think about it when it happens and I'm about to take off! ;-0 I'll have to try that, although if the vibration is being transmitted intothe car chasis I may not be able to narrow it down so easily unless I can actually see the compressor shaking or something.
I'll give it a shot though, thanks...