I don't know if your IS3000 does this as well but mine makes a whistling noise when the A/C is ON. When the blower is on, the noise is not there, only when the A/C light is on. The dealer can not find the problem but the noise is annoying. It is coming from the drivers side. Oh, and it is the A/C vents. I've tested that already. Anyone have any suggestions or the same thing happen to them?