Suzuki: WHIRRING SOUND IN THROTTLE BODY, steth, light thanks

Question
Hi thanks for the answer about putting the tranny in neutral while car is running (automatic 1995 vitara 16v), a few months back I had heard a whirring sound coming from the engine bay, everytime the A/C would go on, at first I thought it was the fan so I disconnected power to it, the noise did not come from it then I thought it was the A/C Comp, but I couldn't pinpoint it, a mechanic once gave me some pointers on listening for engine sounds, we used a small flexible garden hose 1/2" size about a meter long and moved it about the engine bay, just like a steth for a doctor, when I came about the throttle body that was where the sound came from, it sounded like a bad bearing, but everytime the A/C was turned off, the sound immediately died with it...is there any moving part in the throttle body that could make the sound? and why did it only come about when the A/C was on

Hoping that you can shed some light,


Thanks in advance,

Mike

Answer
There's frequency controlled air valve in the throttle body that allows for extra air when the a/c, headlights, or other power consumer is on to keep the idle from dropping too low.

I think what you hear is normal, but if in doubt take it to a mechanic and have him listen.